tenth annual undergraduate seismic design competition (sdc) · 2012. 12. 24. · presentations and...

RULES

Organized and Run by: EERI Student Leadership Council (SLC)

Competition Website: http://slc.eeri.org/SDC2013.htm

Tenth Annual Undergraduate Seismic Design Competition (SDC)

Seattle, WA

2013 Undergraduate Seismic Design Competition- Rules 2

Table of Contents

1. Introduction .......................................................................................................................... 3 1.1 Competition Objectives ..................................................................................................................................... 3

1.2 Problem Statement ............................................................................................................................................ 3 1.3 Eligibility and Registration ............................................................................................................................... 4

1.4 Important Dates ................................................................................................................................................. 5 1.5 Units .................................................................................................................................................................. 5 1.6 Summary of Rule Changes from 2012 .............................................................................................................. 5

2. Scoring .................................................................................................................................. 6 2.1 Presentation, Poster, and Architecture .............................................................................................................. 6

2.2 Performance Predictions ................................................................................................................................... 8

2.3 Annual Revenue ................................................................................................................................................ 9 2.4 Annual Building Cost ........................................................................................................................................ 9 2.5 Annual Seismic Cost ....................................................................................................................................... 10 2.6 Final Annual Building Income ........................................................................................................................ 10

3. Competition Awards .......................................................................................................... 11 3.1 Competition Winner and Ranking................................................................................................................... 11

3.2 Honorable Mentions ........................................................................................................................................ 11 3.3 Best Communication Skills Award ................................................................................................................. 11

3.4 Charles Richter Award for the Spirit of the Competition ................................................................................ 11

3.5 Egor Popov Award for Structural Innovation ................................................................................................. 11

4. Competition Schedule ........................................................................................................ 12

5. Design Proposals ................................................................................................................ 13

6. Structural Model ................................................................................................................ 13 6.1 Structural Model Materials ............................................................................................................................. 14

6.2 Structural Model Dimensions ......................................................................................................................... 14

6.3 Structural Frame Members .............................................................................................................................. 15

6.4 Shear Walls ..................................................................................................................................................... 15 6.5 Structural Connections .................................................................................................................................... 15 6.6 Dead Load Connections .................................................................................................................................. 16

6.7 Floors .............................................................................................................................................................. 16 6.8 Structural Model Base Plate ............................................................................................................................ 17

6.9 Structural Model Roof Plate ............................................................................................................................ 18

6.10 Innovative Damping Devices .......................................................................................................................... 19

6.11 Building Finish ................................................................................................................................................ 19 6.12 Structural Model Weight ................................................................................................................................. 19

7. Strong Ground Motion Testing ........................................................................................ 19 7.1 Scaled Ground Motions................................................................................................................................... 19

7.2 Shake Table ..................................................................................................................................................... 20 7.3 Attachment of Structural Model to the Shake Table ....................................................................................... 20

7.4 Dead Load ....................................................................................................................................................... 20 7.5 Instrumentation ............................................................................................................................................... 21 7.6 Data Processing ............................................................................................................................................... 21 7.7 Evaluating Economic Loss .............................................................................................................................. 21

8. Score Sheets ........................................................................................................................ 24

9. Rule Clarifications ............................................................................................................. 24

10. Judging and Appeals.......................................................................................................... 25

11. Appendix ............................................................................................................................. 26


1. Introduction

The 10th annual Seismic Design Competition will be held in conjunction with the 65th

Earthquake Engineering Research Institute (EERI) Annual Meeting on February 12th through 15th 2013 at the Grand Hyatt in Seattle, WA.

1.1 Competition Objectives

The objectives of the Tenth Annual Undergraduate Seismic Design Competition sponsored by EERI are: • To promote the study of earthquake engineering among undergraduate

students. • To provide civil engineering undergraduate students with an opportunity to

work on a hands-on project designing and constructing a cost-effective frame building to resist seismic loading.

• To promote EERI activities among civil engineering students as well as the general public, and to encourage international participation in these activities.

1.2 Problem Statement

Your team has been hired to submit a design for a multi-story commercial office building in Seattle, WA. The building will assume the place which is currently occupied by the Seattle Space Needle. Your task is to design the new icon building for Seattle. Your team can use the Space Needle as an inspiration for your design or create a completely new icon for the city. The building owner wants to construct a cost-effective structure that is designed for seismic loading. The building owner wants to make use of daylighting in the building for sustainability purposes. The structural design should be designed to allow as much light as possible inside. In addition, the structure should be suitable for use as a multi-story commercial office building. To verify the seismic load resistance system, a scaled balsa wood model, representative of the real building design will be constructed and tested. The model will be subjected to three ground motions, which represent different return period earthquakes. In order to ensure life safety the building model must not collapse during shaking. In addition, the response of the model in terms of roof drift and roof acceleration will be measured during the shaking. For each ground motion, the value of the roof drift will be used to estimate the monetary loss due to damage in the structural and non-structural building components. Likewise, the roof acceleration will be used to estimate the monetary loss due to damaged equipment that is contained inside the building. If collapse occurs, the monetary losses will account for demolishment, reconstruction, and downtime. Finally, the annual seismic cost will be obtained as the sum of the economic loss estimated for each of the earthquakes divided by its return period.


A cost-benefit analysis will be carried out to determine the most cost-effective building. This will be done by balancing the revenue with the initial building cost and seismic cost. • The revenue will be computed as a function of the floor area to be sold or

rented. Bonuses in revenue will be given to those teams with the best architecture, presentation and poster. These bonuses account for the positive effect quality architecture and effective communication skills can have on increasing the value of the floor to be sold or rented.

• The initial cost will be obtained as a function of the weight of the building model. Penalties that increase the initial cost will be applied to those models that exceed the maximum permitted weight and dimensions.

• The seismic cost will be based on the building’s seismic performance. A bonus will be given to the teams with the best performance predictions. This bonus will reduce the seismic cost of the building. This accounts for the fact that a detailed structural analysis can improve structural design leading to better seismic performance.

The winner of the competition will be the team whose building survives the shaking with the highest cost-benefit balance. Teams whose buildings collapse will be ranked in a lower category than teams whose buildings survive.

1.3 Eligibility and Registration All teams interested in participating in the competition are required to pre-register. The pre-registration form will be available online at the competition website listed on the cover page. The pre-registration deadline is listed in Section 1.4. Each team will identify a team captain who will act as the team liaison for correspondence with the Seismic Design Chairs, judges and submitting clarification requests (see Section 9). The 35 teams selected to compete will be required to complete a final registration prior to the competition. The final registration form will be sent via email approximately 2-3 weeks prior to the final registration due date listed in Section 1.4. The following will be strictly enforced:

1. Teams must be affiliated with a registered EERI student chapter. To start a student chapter, please reference the following website:

http://www.eeri.org/about-eeri/student-chapters/how-to-start-an-eeri-student-chapter/

2. Teams may have as many undergraduate student participants as they wish; Graduate students are welcome to assist undergraduate student participants in the competition; however, they cannot register as team members.

3. Each competing university can enter only one student team and one structure at the competition


Team registration questions should be directed to:

[email protected]

1.4 Important Dates Pre-registration November 1st Design proposal Selection of 35 teams

November 15th

December 3rd Registration Performance predictions and floor area calculations

December 14th February 8th

Structure arrival to competition February 12th Presentations and poster session February 13th Shaking February 14th Award Ceremony February 15th

Only eligible teams are allowed to submit a design proposal. For eligibility requirements, refer to Section 1.3.

1.5 Units All measured and specified parameters in the competition will be in English units, inches and pounds. Metric units can be converted to English units by using the following conversion factors: 1 [in] is approximately 2.54 [cm] 1 [lb] is approximately 0.454 [kg]

1.6 Summary of Rule Changes from 2012

1. The base and roof plates will not be mailed to the teams; teams are responsible

for providing two base plates and two roof plates. 2. The scoring weight will not account for the base plate or roof plate 3. The construction cost per pound of weight has changed. 4. Dimensional penalties and weight penalties have changed. 5. Rentable floor area is required to have interior beams that do not allow a 2 1/2"

disc to pass through the floor. 6. The maximum plan view length for shear walls is 2 1/2 in. 7. Clamps will be used to secure the model to the shake table and accelerometer to

the model. 8. A problem statement has been added. 9. A standard procedure for Rule Clarifications has been added. 10. Rules for judging the competition have been added. 11. Teams are required to specify a team captain. 12. Team Captains are required to sign off on penalty sheets. 13. All units in the competition are in English units.


2. Scoring

To verify the seismic load resistance system, a scaled balsa wood model that is representative of a real building design must be constructed and tested. The model will be subjected to three ground motions, which represent different return period earthquakes. In order to ensure life safety the building model must not collapse during shaking. In addition, the response of the model in terms of roof drift and roof acceleration will be measured during the shaking. For each ground motion, the value of the roof drift will be used to estimate the monetary loss due to damage in the structural and non-structural building components. Likewise, the roof acceleration will be used to estimate the monetary loss due to damaged equipment that is contained inside the building. If collapse occurs, the monetary losses will account for demolishment, reconstruction, and downtime. Finally, the annual seismic cost will be obtained as the sum of the economic loss estimated for each of the earthquakes divided by its return period. This section describes the method used to score the performance of the buildings in the seismic competition. Scoring is based on three primary components: 1. Annual revenue, 2. Annual Building Cost, and 3. Annual seismic cost. The final measure of structural performance is the annual income, which is calculated as the annual revenue minus the annual building cost minus the annual seismic cost. An example problem in the Competition Guide demonstrates the scoring method.

2.1 Presentation, Poster, and Architecture

Bonuses in revenue will be given to teams whom rank highest in either the presentation, poster, or architecture scores. These bonuses account for the positive effect of having effective communication skills or architectural appeal that could increase the value of the floor to be sold or rented.

2.1.a Presentation

Each team is required to give a five-minute oral presentation to a panel of judges. Judges will have three minutes to ask questions following the presentation. The presentations will be open to the public.

A projector and laptop, running Microsoft Windows 7, and PowerPoint (Office 2007 or newer) will be provided. The presentation files should be uploaded to the competition laptop before the first presentation. Teams are responsible for software compatibility. Teams can email their presentations to the organizing committee; however, it is recommended to bring a USB memory stick as well. See the Competition Guide for the judge’s score sheet that will be used.


2.1.b Poster Teams are required to display a poster providing an overview of the project. The dimensions of the poster are restricted to a height of 42 in. and a width of 36 in. The minimum font size for all text shall not be less than 18. The university name, EERI logo, and SLC logo should appear at the top of the poster. A font size of 40 is recommended for the university name. See the Competition Guide for the judge’s score sheet that will be used.

2.1.c Architecture To be considered for the architecture bonus, teams must satisfy all requirements in this section: The university name should be placed at the top of the building, on a banner or paper (non-structural element). The dimensions are restricted to a width of 6 in and depth of 1 in.

2.1.d Bonus Scoring

The increase in Annual Revenue will be determined by the team’s rank in the oral presentation, poster, and architecture. Only the top 10 teams in the presentation and poster category will receive this benefit. The top 5 teams in the architecture category will receive this benefit. See Table 2-1 for the percentage increase per rank.

Table 2-1: Annual Revenue Bonus

Rank

Presentation Poster Architecture

1st 15% 10% 5%

2nd 12% 9% 4%

3rd 10% 8% 3%

4th 8% 7% 2%

5th 6% 6% 1%

6th 5% 5% 0%

7th 4% 4% 0%

8th 3% 3% 0%

9th 2% 2% 0%

10th 1% 1% 0%

11th> 0% 0% 0%


2.2 Performance Predictions A bonus will be given to the teams with the best performance predictions. This bonus will reduce the seismic cost of the building. This accounts for the fact that a detailed structural analysis can improve structural design leading to better seismic performance. Teams are required to predict the absolute value of the peak roof drift and the peak roof absolute acceleration for all three ground motions. Although performance predictions for all three GM’s are required, only the performance predictions for GM1 will affect the annual income. The performance predictions must be sent in by the date listed in Section 1.4.

2.2.a Performance Predictions Requirements

The Annual Seismic Cost will be reduced based on the team’s rank in the performance predictions for GM1. Each team is required to report for each ground motion: Predicted Drift = max | Roof Displacement [in] – Base Displacement [in] | Predicted Acceleration = max | Acceleration [% g] | The Analysis Predicted Score (APS) is used to evaluate the accuracy of the predicted performance (taken to two significant figures). APS1 is for the maximum absolute roof drift prediction while APS2 is for the peak roof absolute acceleration. See section 7.7.b for how the measured Peak Drift Ratio and Peak Acceleration are determined. APS1 = | (Predicted Drift / Structural Model Height – Peak Drift Ratio) | . Peak Drift Ratio APS2 = | (Predicted Acceleration – Peak Acceleration) | . Peak Acceleration APS = APS1 + APS2 Each team will be ranked based on the accuracy of the predictions for GM1. The lowest APS is awarded to most Analysis Prediction Score Bonus (APS Bonus). See Table 2-2 for the percentage increase per rank.


Table 2-2: Analysis Prediction Score Bonus

Rank APS Bonus

1st 15% 2nd 12% 3rd 10% 4th 8% 5th 6% 6th 5% 7th 4% 8th 3% 9th 2% 10th 1%

11th> 0%

2.3 Annual Revenue Annual building revenue will be based on the total rentable floor area, with higher floors commanding more revenue per square inch than lower floors: $125 per year per square inch for floors 1 through 15 $175 per year per square inch for floors 16 through 24 $225 per year per square inch for floors 25 and above Each individual rentable floor area is calculated using the total plan area defined by the perimeter beams and meeting the Section 6.7.b requirements. Individual structural members (columns, shear walls, and braces) are not subtracted from the rentable floor area. Max rentable total floor area: 4650 in2 The total rentable floor area will be calculated by summing the individual floor areas from the bottom up. The individual floor area of any story that exceeds the maximum allowable height will not be counted. The Annual Revenue is equal to the sum of each rentable floor area multiplied by its respective revenue per square inch factor.

2.4 Annual Building Cost The Annual Building Cost will be obtained as a function of the Structural Model Weight and the building footprint. $35,000 per square inch of building footprint $9,000,000 per pound of Structural Model Weight


The building footprint is defined as the maximum floor plan projected onto the base plate. The Structural Model Weight does not include the weight of the base and roof plates and does not include the dead load weights added during shaking. The Structural Model Weight is subject to penalties described in Sections 6.8.b and 6.9.b. The Annual Building Cost will be computed by dividing the cost of the land and the construction by the design life of the building (100 years).

2.5 Annual Seismic Cost

The Annual Seismic Cost will be based on the building’s seismic performance. The evaluation of economic loss procedure is described in Section 7.7. The Equipment Cost is used for the in the evaluation of economic loss procedure detailed in Section 7.7 and is equal to: Equipment Cost = $20,000,000 The Annual Seismic Cost is equal to: Annual Seismic Cost = Annual Economic Loss1 [$] + Annual Economic Loss2 [$]

+ Annual Economic Loss3 [$]

2.6 Final Annual Building Income

The final score for each team will be calculated in terms of the annual income. The team with the greatest Final Annual Building Income (FABI) will be the winning team. FABI is equal to the Final Annual Revenue (FAR) minus the Final Annual Building Cost (FABC) and Final Annual Seismic Cost (FASC). Penalty Factors

N: Building Dimension Penalty (see Section 6.1-6.5) M: Building Weight Penalty (see Section 6.8, 6.9, 6.12) D: Failed Connections Penalty (see Section 7.7.c)

Final Annual Revenue (FAR) can be expressed as:

FAR = (1+Presentation Bonus+Poster+Arch. Bonus) x Annual Revenue

Final Annual Building Cost (FABC) can be expressed as:

FABC = (1+N+M) x Annual Building Cost

Final Annual Seismic Cost (FASC) can be expressed as:

FASC = (1+D – APS Bonus) x Annual Seismic Cost


The Final Annual Building Income (FABI) can be expressed as:

FABI = FAR – FABC – FASC

3. Competition Awards

3.1 Competition Winner and Ranking The team that designs the building that is not deemed collapsed in any of the three ground motions with the highest Final Annual Building Income will be the winner of the competition.

Teams whose buildings collapse will be ranked in a lower category than teams whose buildings do not collapse. Within each category, teams will be ranked based on the Final Annual Building Income. The teams ranked overall 2nd and 3rd will also be awarded.

3.2 Honorable Mentions Two honorable mentions will be awarded for the best teams in individual aspects of the competition:

1. An Honorable Mention for Best Architecture will be awarded to the team

ranked 1st in architecture. 2. An Honorable Mention for Best Seismic Performance will be awarded to the

team with the lowest Annual Seismic Cost.

3.3 Best Communication Skills Award An award will be given to the team whom has the highest combined presentation and poster scores using the equation below. In the case of a tie, the team ranking higher in the architecture category will win.

Total score = 1.5 x Presentation score + Poster score

3.4 Charles Richter Award for the Spirit of the Competition The most well-known earthquake magnitude scale is the Richter scale which was developed in 1935 by Charles Richter, of the California Institute of Technology. In honor of his contribution to earthquake engineering, the team which best exemplifies the spirit of the competition will be awarded the Charles Richter Award for the Spirit of Competition. The winner for this award will be determined by the participating teams.

3.5 Egor Popov Award for Structural Innovation

Egor Popov had been a Professor at the University of California, Berkeley for almost 55 years before he passed away in 2001. Popov conducted research that led to many advances in seismic design of steel frame connections and systems, including eccentric bracing. Popov was born in Russia, and escaped to Manchuria


in 1917 during the Russian Revolution. After spending his youth in China, he immigrated to the U.S. and studied at UC Berkeley, Cal Tech, MIT and Stanford. In honor of his contribution to structural and earthquake engineering, the team which makes the best use of technology and/or structural design to resist seismic loading will be awarded the Egor Popov Award for Structural Innovation. The winner for this award will be determined by the SLC members.

4. Competition Schedule The following events happen at the competition. The schedule is subject to change and will be announced after the final registration date.

1. If structural models are shipped to the conference hotel, ensure the delivery date is before

the official start of the competition. Structural models can be unpacked in a designated area. If a structure is damaged during transportation, it may be repaired before the oral presentations begin.

2. A mandatory team captain meeting will occur the morning before oral presentations. The judges will go over the schedule and procedures for the competition. One representative from each team is required. If the team captain cannot attend the meeting, another team member may attend in place of the official team captain. Lack of attendance to the captain’s meeting will not constitute an excuse for not knowing the competition schedule and procedures.

3. Oral presentations will take place on the first day of the competition. The order of the presentations will be announced the morning of the oral presentations. The judges may only announce the order of several teams at a time. Once the first presentation begins, structural models must be on display in the designated display area and cannot be modified. See Section 3.1.a for presentation requirements.

4. A poster and structural model display session will occur at the end of the day and

coincide with the EERI Annual Meeting poster session.

5. Judges will inspect structural models for penalties. Judges will collect a secondary base plate and roof plate from each team for weighing (see Sections 6.8 and 6.9).

6. Structural model shake testing will occur the next day after the presentations, display and

poster session. Team order will be determined and announced at the competition. The judges will flip a coin to determine the direction of shaking before the first shake test begins.

7. All competition awards will be announced at the closing EERI Annual Meeting Banquet.


5. Design Proposals Your team should submit a proposal for evaluation by the SDC chairs of the EERI Student Leadership Council. The following is an itemized list of the deliverables required in your proposal:

• Names of all team members, designating the team captain (this person will be the only point of contact between the team and the SDC chairs for the duration of the design and until the completion of the competition).

• General description of the design, noting key concepts with regards to architecture, structural innovation, sustainability, etc.

• Detailed description of all damping devices. Due to limited resources, only 35 teams will be able to participate in the seismic design competition. If more than 35 teams register, those with the best design proposals will be selected to compete. The design proposal should highlight:

• Function: creativity and suitability of the proposed idea given the local and

geographical concerns and the specific type of use deemed for the building • Quality: cost-efficiency, sustainability, innovation • Context: how the building fits into its environment

Your proposal should be a maximum of two pages (including figures), 11pt, single-spaced, Times New Roman font with 1” margins. A PDF of the document must be emailed to the SDC chairs at the following email address by the date listed in Section 1.4.

[email protected]

Design proposals are not being evaluated for rule violations. Selected designs are still subject to penalization. Damping devices are the only item that must be pre-approved; they are approved during the design proposal selection. Teams are allowed to deviate from their original designs, but any major revisions are prohibited. Teams are responsible for ensuring that their buildings follow the competition rules. For any clarification, see the clarifications section posted on the competition website or the team captain can submit a clarification request (see Section 9).

6. Structural Model

This section describes the rules and limitations to be followed for the structural model. Any violation will result in building dimension penalty factor (N) or building weight penalty factor (M). Failure to comply with any of these requirements may result in penalization or even disqualification. Penalties will be given at the discretion of the judges.


Structural models shall be constructed of structural frame members (see Section 6.3) and shear walls (see Section 6.4) that are attached to a structural model base plate (see Section 6.8) with a structural model roof plate attached on top of the structural model (see Section 6.9). All connections requirements are in Section 6.5.

6.1 Structural Model Materials Any structural frame member and shear wall in violation of this section will result in disqualification. All structural frame members and shear walls shall be made of balsa wood.

6.2 Structural Model Dimensions

6.2.a Plan Dimensions and Floor height Each dimensional violation in this section will result in 2% added to N per 1/8 in. of deviation. Measurements will be rounded up to the nearest deviation. Teams will not be penalized for the first 1/8 in. of deviation. Max. floor plan dimension: 15 in. x15 in. Min. individual floor dimension: 6 in. x 6 in. Individual Floor height: 2 in. Lobby level height (1st level): 4 in. 10th floor height: 4 in.

6.2.b Floor Levels

Each violation in this section will result in 10% added to N per level of deviation. Max number of floor levels: 28 levels Min number of floor levels: 15 levels

6.2.c Total Structural Model Height Each dimensional violation in this section will result in 5% added to N per 1/4 in. of deviation. Measurements will be rounded up to the nearest deviation. Teams will not be penalized for the first 1/4 in. of deviation. Total structural model building height shall be equal to: Structural Model Height = 2 [in.] x (No. of floors) + 4 [in.] Structural height shall be measured from the base floor to the top of the uppermost frame member of the top level. The base floor is defined as the top of the base plate.


6.3 Structural Frame Members Each dimensional violation of 1/8 in. deviation in this section will result in 1% per story added to N. If a structural frame member spans multiple floors, the penalty will be multiplied by the number of floors it spans. Dimensions between increments will be rounded up. The maximum member cross section dimensions are:

Rectangular member: 1/4 in. x 1/4 in. Circular member: 1/4 in. diameter

6.4 Shear Walls

6.4.a Shear Wall Dimensions Each dimensional violation of 1/8 in. deviation in this section will result in 1% per story added to N. If a shear wall spans multiple floors, the penalty will be multiplied by the number of floors it spans. Dimensions between increments will be rounded up. Shear walls must comply with the following requirements: Maximum thickness: 1/8 in. Minimum length (plan view): 1 in. Maximum length (plan view): 2 1/2 in.

6.4.b Shear Wall Requirements

Each violation of this section will result in 5% added to N.

Shear walls must span at least one floor. The ends of structural frame members can attach to shear walls, but must meet the same requirements as moment connections. The only exception is vertical columns can be connected full height along the short edge of shear walls. In plan view, shear walls shall not be in contact except in the case of the short side of one shear wall connecting to the long side of an adjacent shear wall.

6.5 Structural Connections

6.5.a Structural Connection Requirements Each violation of this section will result in 5% added to N. Connections of structural members can be made only from glue. All members and walls in contact with the base plate must be glued to the base plate.

6.5.b Structural Connection Dimensions

Each dimensional violation in this section will result in 1% added to N. Measurements will be rounded up to the nearest deviation.


The height and length of moment frame connections shall not exceed 3 times the maximum cross sectional dimension of the structural frame members being connected, as shown in Appendix Figure A-5. The thickness of the connection shall not exceed the minimum cross sectional dimension of the members being joined. Gusset plates may be added to each side of a connection as long as the sum of the thicknesses of each gusset plate does not exceed the minimum cross sectional dimension of the members being joined.

6.6 Dead Load Connections

Dead load will be added to the structural model prior to shake testing (see Section 7.4). The dead load will require sufficient support for gravity loading and lateral seismic loading. Dead load connections are required in both North-South and East-West directions and to be centered in plan view in relation to the center of the base plate. Dead load will be secured to the structure using nuts and washers; they cannot be secured to the floor beam alone. See the Appendix Figure A-2 and A-3 for a picture of the dead load weights and diagrams and the Competition Guide for examples a typical dead load attachment. It is strongly recommended that each team purchase a sample weight to try out and ensure proper attachment. Penalties will be assessed for dead weights that are not secured to the structural model after each ground motion testing and may result in judges deeming the building collapsed. Washers, nuts, or plates may not penetrate the exterior face of the building defined by the edge of the perimeter beams. The dead weights should be able to be installed and nuts be tightened to ensure a snug fit without breaking any of the structural connections, structural frame members, or shear walls in the structural model.

6.7 Floors 6.7.a Floor Isolation

Any violation of this section will result in disqualification from the competition. Floor isolation of any kind is not allowed.

6.7.b Floor Requirements Any floor that violates the requirements in this section shall not count towards rentable floor area. Each floor must have a system of perimeter and interior beams to clearly define the floor area. The perimeter beams must be continuous. The plane defined by the top of the perimeter beams must be flat and level.


A 2 1/2 in. diameter disc shall not be able to penetrate the plane from the top of the floor defined by the perimeter beams at each floor. Floor area not counted as rentable floor area does not need to meet this requirement.

Each floor must be legibly labeled for judges to see. The floor at the base of the building will be labeled ground, and the floor above the lobby, 2nd. The label is not required to be made of balsa wood but must not be designed to assist in the structural performance or interfere with the installation of the dead weights. Occupants on the rentable floor should be able to access any area of the rentable floor through at least two access points or doorways. A sufficient access point is defined as a clear opening with the following minimum dimensions:

Width: 1 in. Height: 1.5 in.

6.8 Structural Model Base Plate

6.8.a Structural Model Base Plate Plan Dimensions Each dimensional violation in this section will result in 10% added to N per 1/8 in. of deviation. Measurements will be rounded up to the nearest deviation. Teams will not be penalized for the first 1/8 in. of deviation. An 18 in by 18 in square continuous plywood base plate will be used to attach the building to the shake table. Teams are responsible for providing a plywood base plate. All components of structural model shall not be closer than 1 in from the outside edge of the structural model base plate.

6.8.b Structural Model Base Plate Thickness Dimensions The plywood base plate shall be 3/8 in. If the measured thickness is less than 3/8 in., judges will measure the actual thickness and calculate an estimate of the weight if the base plate were 3/8 in. As a penalty, the difference in the measured weight and estimated weight would be added to the Structural Model Weight in Section 2.4.

6.8.c Structural Base Plate Requirements Notching the base plate is allowed, but only if it is to frame members and walls. Teams are not allowed to trim the base plate to save weight. Any violation of notching to save weight will result in 50% added to M.


A vertical 1/8 in diameter hole shall be drilled through the structural model base plate 9 in. from one side and 3/4 in. inside from an edge. The hole will designate the north side of the plate. If a hole in the base plate is not present at the competition, a judge will mark the base plate to designate the north side. A second identical 18 in x 18 in square continuous 3/8 in thick plywood base plate shall be provided by the team for judges to weigh in lieu of weighing the base plate attached to the structural model. If the judges deem the second base plate is not identical, the judges will remove the structural model from the original base plate after testing and weigh the original plate instead. Identical notching is not necessary in the second base plate.

6.9 Structural Model Roof Plate

The structural model roof plate will be where the accelerometer is attached for shaking. Care must be taken when designing the roof beams to allow for two C-clamps to clamp the accelerometer to two diagonally opposing corners of the structural model roof plate. The structural model roof plate shall be level when attached to the structural model.

6.9.a Structural Model Roof Plate Plan Dimensions Each length dimensional violation in this section will result in 10% added to N per 1/8 in. of deviation. Measurements will be rounded up to the nearest deviation. Teams will not be penalized for the first 1/8 in. of deviation. A 6 in by 6 in square continuous plywood roof plate is needed to attach the accelerometer to the building.

6.9.b Structural Model Roof Plate Thickness Dimensions The plywood roof plate shall be 3/8 in. If the measured thickness is less than 3/8 in., judges will measure the actual thickness and calculate an estimate of the weight if the base plate were 3/8 in. As a penalty, the difference in the measured weight and estimated weight would be added to the Structural Model Weight in Section 2.4.

6.9.c Structural Model Roof Plate Requirements Notching the roof plate is allowed, but only if it is to frame members and walls; that is, you cannot remove material from the roof plate to save weight. Teams are not allowed to remove material from the base plate to save weight. Any violation of notching to save weight will result in 50% added to M.


A second identical 6 in x 6 in square continuous 3/8 in thick plywood roof plate shall be provided by the team for judges to weigh in lieu of weighing the roof plate attached to the structural model. If the judges deem the second roof plate is not identical, the judges will remove the roof plate from the structural model after testing and weigh the original plate instead. Identical notching is not necessary in the second base plate.

6.10 Innovative Damping Devices

All dampers must be approved in the proposal submission process. Any use of a damping device that is not pre-approved in the proposal process will result in disqualification. Any material is allowed to manufacture a damper. The implementation of such a device needs to allow for the placement of weights as discussed in Section 7.4.

6.11 Building Finish

The building finish must be bare wood. Paint or other coatings will not be allowed on the building. Teams may be disqualified if judges deem the building finish is not bare wood.

6.12 Structural Model Weight

For each 0.10 lb increment over the allowable weight 10% will be added to M. A weight between increments will be rounded up.

The total weight of the structural model, including the base and roof plates and any damping devices, should not exceed 4.85 lbs.

7. Strong Ground Motion Testing

The building will be subjected to three ground motions of increasing intensity. The structural response to all three ground motions will contribute to the annual seismic cost. If time does not allow, only two of the ground motions will be used for the competition. The decision will be made by the SLC on the day of the competition based on time constraints and the number of teams. Horizontal acceleration will be measured in the direction of shaking using accelerometers mounted on the roof of the structure and on the shake table as shown in Appendix Figure A-4.

7.1 Scaled Ground Motions

Structures will be subjected to 3 scaled and modified ground motions named GM1, GM2, and GM3.

It is imperative for teams to download all the ground motions from the competition website and not from any other sources, since the records have been compressed in time and scaled to meet the limits of the shake table.


The ground motion records are available at the competition website listed on the cover page.

7.2 Shake Table

Structures will be tested on the University Consortium for Instructional Shake Tables (UCIST) unidirectional earthquake shake table, with plan dimensions of 18.0 in. by 18.0 in. and a payload capacity of 33 lb.

7.3 Attachment of Structural Model to the Shake Table Judges will determine the direction of shaking by flipping a coin prior to shake testing. The coin flip will determine if shaking is in the north-south direction or east-west direction. One coin will be flipped and all structural models will be tested in the same direction. Judges will attach the structural models to the shake table with four C-clamps at the corners of the structural model base plate. If the base plate is warped, the corners of base plate will be clamped so there are no gaps at the corners between the shake table and the base plate.

7.4 Dead Load

Each floor dead load will be represented by a steel threaded bar and 8 plates (Simpson Strong Tie BP 5/8-2) tightened with 4 washers and 4 nuts. These will be firmly attached to the frame in the direction perpendicular to shaking. See the Appendix Figure A-2 and A-3 for exact dimensions and figures. The roof dead load will be represented by the accelerometer and steel plate including two C-clamps to secure the accelerometer and steel plate to the building. See the Competition Guide for a representative breakdown of the weights for each component. Floor weight: 2.7 lbs

Roof weight: 3.5 lbs Weight spacing: 6 in. Threaded bar diameter: 1/2 in. The dead load will be placed at floor levels in increments of 6 in. In cases where a floor does not exist at an exact increment of 6 in, the weight will be attached to the nearest higher floor.

The total added roof dead weight will be 3.5 lbs, and will consist of a steel plate with dimensions of 6 in x 6 in x 1/2 in, an accelerometer, and two C-clamps. See Appendix Figure A-1 for roof configuration. Note: The listed roof weight does account for the included the weight of the structural model roof plate.


7.5 Instrumentation Two accelerometers will be used in the competition: one accelerometer will be attached onto the shake table, and the other accelerometer will be attached onto the roof plate with two C-clamps.

7.6 Data Processing

Displacements will be computed from each recorded acceleration time series by performing the following steps: 1. Transfer the acceleration records into the frequency domain using a Fourier

transform. 2. Digitally high-pass filter the acceleration recordings in the frequency domain

using a 3rd order Butterworth filter with a corner frequency of 0.8 Hz. 3. Transfer the acceleration from the frequency domain to the time domain. 4. Numerically double integrate the filtered acceleration records over time to obtain

displacements. A portion of the low-frequency range of the raw acceleration signals must be removed using a digital filter prior to double integration because the low frequency content of the signals is small compared to the noise. Highly unrealistic displacements would be obtained if the raw data were integrated in time without first filtering some of the low frequency content because of the low-frequency noise. An undesired but unavoidable consequence of the filtering is that the low-frequency portion of the acceleration signals, which contains permanent displacements, must be removed. As a result, the displacements computed by double-integrating the acceleration records are transient displacements; the low-frequency permanent component will not be reflected in the computed displacement time series.

7.7 Evaluating Economic Loss The annual economic loss for a given ground motion will be computed as the economic loss for that ground motion divided by its Return Period, which is indicated in Table 7-1. Annual seismic economic loss will be computed by summing the annual economic loss for all ground motions imposed to the structural model.

Table 7-1: Return periods for ground motions used in competition.

Ground Motion Return Period [Years]

GM1 50

GM2 150

GM3 300 The economic loss for collapsed models should use Section 7.7.a. The economic loss for non-collapsed models should use Section 7.7.b.


7.7.a Collapse Occurs

Collapse is considered if the judges deem that the structural model has failed. This includes, but is not limited to, a significant portion of the structural model falling from the shake table, 50% or less of the weights are restrained by the structure at their initial pre-shaking location on the structural model, or more than 50% of the vertical columns and shear walls attached directly to the base plate are separated from the base plate or the rest of the structural model. If collapse occurs, the Economic Loss and Annual Economic Loss corresponding to ground motion n will be equal to: Economic Lossn = Equipment Cost [$]+ 2 x Construction Cost [$]

+ 3 x Annual Revenue [$]

Annual Economic Lossn = Economic Lossn [$] / Return Periodn [Years] A panel of judges will decide if a building is classified as collapsed. If collapse occurs during GM1 or GM2, collapse will be assumed to happen for the subsequent ground motions for loss calculation purposes.

7.7.b Collapse Does Not Occur

The economic loss from each ground motion will be assessed using loss functions that relate economic loss to two engineering demand parameters (EDP) measured during shaking: EDP1 = Structural damage as a percent of Initial Construction Cost [%] EDP2 = Equipment loss as a percent of Equipment Cost [%] The two economic loss factors are related to two measured parameters during ground motion shaking: Peak Drift Ratio = max |(∆Roof [in] – ∆Base [in]) | .

Structural Model Height [in]

Peak Acceleration = max | Acceleration [g] |

1. Economic loss due to structural damage Structural damage to the building will be assessed using Peak Drift Ratio. The loss function relating cost of structural damage to drift ratio is defined as a cumulative normal probability density function with mean drift ratio of 0.015 and a standard deviation of 0.005. The loss function is plotted in terms of normalized cost (EDP1) in Figure 7-1.


Tip: The distribution function can be computed using many commercially-available software packages (e.g. the NORMDIST function in Microsoft Excel, with the 'cumulative' field set to TRUE).

Figure 7-1: Loss function relating relative structural repair cost to peak drift ratio (EDP1)

2. Loss Caused by Equipment Damage (EDP2) The building is assumed to house equipment worth Equipment Cost that is sensitive to the floor acceleration. Damage to this equipment will be related to Peak Acceleration using a loss function that is a cumulative normal probability density function with mean peak roof acceleration of 1.75g, and standard deviation of 0.7g. The loss function (EDP2) is plotted in Figure 7-2.

Figure 7-2: Loss function relating equipment cost to peak roof acceleration (EDP2)

0

0.2

0.4

0.6

0.8

1

0 0.005 0.01 0.015 0.02 0.025 0.03

ED

P1

Peak Drift Ratio [%]

max | (Δ_roof - Δ_floor) / Structural Model Height |

0

0.2

0.4

0.6

0.8

1

0 0.5 1 1.5 2 2.5 3 3.5

ED

P2

Peak Acceleration [g]

max | Acceleration|


The Economic Loss and Annual Economic Loss for a given ground motion n will be equal to: Economic Lossn = EDP1 [%] x Initial Construction Cost [$]

+ EDP2 [%] x Equipment Cost [$]

Annual Economic Lossn = Economic Lossn [$] / Return Periodn [Years]

7.7.c Penalties After each ground motion the judges will inspect the building for failed connections. Failed connections are deemed any weight that have fallen off or significantly detached from the original floor structural system. There will be a 5% increase in D for each loosened threaded bar. After GM1 and GM2, the judges will inspect the accelerometer and roof plate connection to the structural model. If the judges deem the roof plate is not secured to the structural model after testing, the score will assume maximum structural and equipment damage. If the accelerometer is not able to be properly attached and secured to the structural model after GM1, the accelerometer will be removed for GM2 and maximum structural and equipment damage will be assumed for both GM1 and GM2. An unstable roof plate is not grounds to declare a structural model collapsed.

8. Score Sheets

All penalty score sheets will be reviewed and signed by the team captain. The team captain can appeal a penalty (see Section 10). After the appeals process, if the team captain does not sign off on the penalty score sheet, the team will be disqualified.

9. Rule Clarifications

All rule clarifications requests and answers will be posted on the competition website. The posted question and answer will also include the name of the school submitting the question. To submit a rule clarification, the team captain must fill out and submit an online submission form. Questions or clarifications about the rules sent via email will not be answered. Be sure to read the rules and guide thoroughly before submitting a question. An email will be sent out to the team captains and advisors when an update is made to the clarifications page.


10. Judging and Appeals

Judges have complete authority over the interpretation of the rules and oversight of the competition. Judges are responsible for scoring and decisions. All decisions made by the judges are final. Only a team captain may discuss decisions or appeals to judges. Judges will refuse to discuss a decision or appeal to anyone other than the team captain. A team captain may only make an appeal regarding his or her team. If a team captain makes an appeal about a penalty or decision, a second judge will be consulted. After consultation, the decision between the two judges will be final and recorded on the score sheet.


11. Appendix Typical Accelerometer Attachment Elevation View Diagram

Figure A-1: Weight and Accelerometer at Roof Level Dead Load Weight Dimensions

Figure A-2: Dimensions for the Anchors used to Attach Weights

16 inches


Dead Load Attachment Diagram

Figure A-3: Anchorage of Weights to Structure


Schematic Instrumentation

Figure A-4: Schematic of instrumentation layout and measured engineering demand parameters.

Allowable Moment Frame Connection Detail

Figure A-5: Allowable Moment Frame Connection Detail

tenth annual undergraduate seismic design competition (sdc) · 2012. 12. 24. · presentations and...

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