Caltrans Structure Maintenance and Investigations Specialty Investigations, Emergency Response Dolores Valls, State Bridge Maintenance Engineer Chief, Structure Maintenance & Investigations Stephen Sahs, Senior Bridge Engineer SM&I Emergency Response Coordinator

Structures Maintenance and Investigations (SM&I) SM&I offices are located in Sacramento, Oakland, and Los

Angeles. All our inspectors are NHI Certified Bridge Inspection

Team leaders and 95% are licensed Civil Engineers. SM&I primary duty is to inspect bridges (+24,000 bridges

state wide) every two years as required by FHWA. SM&I also responds to any bridge related emergencies. SM&I has close to 250 combined years of emergency bridge

inspection experience.

SM&I Response duties Historically SM&I has responded to every minor and major event

that involves the safety of California’s bridges. SM&I is the lead Department in all bridge related emergencies.

Structure Design and Construction take direction from SM&I Engineers until the bridge is deemed safe and/or repairs have begun.

After a large event such as Northridge earthquake, SM&I will inspect and document all earthquake related bridge damage in an official signed report.

No-damage reports are also written and will include all the bridges in the effected area. This may take several weeks, but regardless of who inspected the bridge first, SM&I will always have a report on every bridge.

California State First Responders “The first Caltrans employees to arrive on a bridge

emergency are the First Responders”. This includes bridge crews, road maintenance crews,

construction personnel, etc. SM&I inspectors are considered second responders. For all

intensive purposes, our inspectors will never be the first to arrive upon a damaged bridge.

First Responders There are four categories of large bridge emergencies that need

immediate attention and any delay would endanger the public. Fires Floods Earthquakes High Load Hits

SM&I relies on the “first” eyes on the scene to give a quick safety assessment and decide to close the road/bridge until an “engineering” assessment can be made. Only after our inspectors make their inspection would a bridge be re-opened.

First Responders Duties for Bridge Emergencies Ensure the safety of the public on roads and bridges Rapid safety assessment for weakened bridges or collapsed

bridges Lane closures maybe required Report to SM&I bridge condition information

Bridge location and quick assessment of the bridges will help direct SM&I resources.

A No-damage report is as important as a damage report because SM&I keeps track of all bridges.

Note: Closing a bridge can never put the public in harms way. BUT, opening a closed bridge prematurely could be disastrous

which is why only our Certified Bridge Inspectors may reopen a closed bridge.

First Responder Assessment Guide (FRAG) The following are examples of our First Responder

Flow Charts and FRAG Fire/Extreme Heat Floods Earthquakes High load hits

Fire/Extreme Heat Bridge Assessments: Concrete Bridges: Columns and Girders

What to look for: Pinkish residue on concrete surface signifies there was enough heat to cause concrete damage. A whitish-grey color, powdered dehydrated paste with spalls Spalls or popped out concrete and exposed rebar with the pinkish or white ash color.

Concern: Concrete Girders: Most fire damage is superficial unless it is heated sufficiently to cause the color

change. Rebar will be affected causing it to expand creating spalls. Pre-stressed I-girders have tendons that if damaged, the girder would have to be replaced.

Concrete Columns: Most fire damage is superficial unless it is heated sufficiently to cause the color change. Rebar will be affected causing it to expand creating spalls. Columns capacity will not be affected unless the heat damaged concrete reaches the concrete inside the spiral rebar.

Action: Set up lane/road/bridge closures on both sides Notify SM&I of a closed bridge Send any photos and information to SM&I

Concrete cover affected, check core for soundness Pinkish surface of heat damaged concrete

Large area of soot and smoke with spalls Open, pinkish spalls would require sounding

Fire - Concrete

FRAG Flood Damage Tab

Flood Response First Responder Duties: Ensure the safety of the public for roads and bridges Follow Scour Plan of Action for those bridges that are identified as Scour Critical Rapid safety assessment for collapsed bridge, flooded approaches, and bridge threatening high flow

conditions Open with no damage Road closed due to high water/flooding Approaches washed out Erosion threatening bridge supports Heavy debris threatening columns

The following information will help the First Responder to make a quick judgment on the safety of a

bridge. There will be several places to look on a bridge that will give you enough information to make a common sense decision to close a bridge.

The primary causes of bridge failure are:

Bank erosion near or at abutments and columns Swift water at soffit level or higher Heavy debris at column(s) Footings and supports scoured away

Flood Response

Pier walls and columns: What to look for:

Railings or deck sagging greater than 2 inches (use best judgment). Misalignment of the railings and abutment joints. Sagging or movement over a pier or column. Pier or column leaning or rotating.

Concern: Loss of support for piers and columns will cause collapse Settling of the bridge if no collapse then is a driving safety concern

Action: Set up lane/road/bridge closures on both sides Notify SM&I of a closed bridge Follow Scour Plan of Action where applicable Send any photos and information to SM&I Site monitoring maybe required

Flood Response

Abutments and Wingwalls: What to look for:

Channel erosion directly upstream or downstream of the road approach, wingwall, and/or abutment.

Concern: Continual erosion may cause loss of support for wingwall and abutment Approaches are most vulnerable if erosion proceeds behind the

wingwalls Permanent settling of the bridge

Action: Set up lane/road/bridge closures on both sides Notify SM&I of a closed bridge Follow Scour Plan of Action where applicable Send any photos and information to SM&I Site monitoring may be required

Continued scour would have taken out the approach. During the event this approach would have been monitored.

This column had failed during the flash flood. If seen at high water, only the angle would be an indication of any damage. See the column to right as an example. Bridge would be closed until a complete assessment can be made after the event by SM&I Engineers.

Flood Response – Columns/Piers/Piles

Earthquake Response The Field Earthquake Responder Assessment is basic safety

bridge damage assessment after a seismic event. After 1971 San Fernando Earthquake a statewide retrofit program

was started. Each seismic event gave the bridge designers more response information and the seismic designs were improved. The threshold magnitudes for any visible damage have increased from a low 5.2 in 1984, to 5.8 in 1994, and to a 6.2 in 2010.

Since the 1994 Northridge earthquake (6.7 mag.) to date, all

seismic retrofits have been completed and new seismic design criteria are used. SM&I have not found any major earthquake related bridge damage for any magnitudes under 6.5.

Scope of a very large event Northridge EQ, 6.7 mag, damaged approximately 300

bridges. SM&I inspected 2000 bridges. For a 7.8 mag., as in the Southern Ca. Golden Guardian in

’08 scenario, there would have been 2000 bridges damaged and SM&I would have to inspect 4000-5000 bridges producing reports on each bridge.

The best use of our field resources will be very quick close/open bridge assessments by the first and second responders. Any damage that does not cause a bridge to close will not be of any importance. But later it would all be quantified.

1994 Northridge EQ, 6.7 Magnitude (Shakecast)

Approximately 300 damaged bridges, 7 collapsed SM&I documented over 2000 bridge inspections

Golden Guardian 2008 – 7.8 Magnitude Estimated 2000 damaged bridges, 4000 bridges would need inspections The red circle is the actual Northridge effected area.

1994 Northridge 6.7

Earthquake Response First Responder Duties:

Ensure the safety of the public on roads and bridges. Rapid safety assessment for collapsed bridges and route safety focusing on

Open with no damage Collapsed or closed due to major damage Closed requesting a SM&I inspection

Report to SM&I bridge condition information The following information will help the First Responder to make a quick

judgment on the integrity of a bridge.

Primary conditions which will cause a bridge to close: Failed Columns Hinges: Unseating or broken seats supports Unseating of girders Approaches settling over 3 inches.

Earthquake Response Approaches: Bridge can be inaccessible because of failed approaches. Asphalt approaches can settle

below the edge of the deck. Anything over 3 inches should be leveled and tapered to the deck grade. What to look for:

Settlement of the approach roadway of either AC or slab type of approach over 3 inches. Determine if the vertical offset is caused by the approach settling or the bridge deck settling. The bridge settling is of more concern and further inspection will be required under the bridge

Concern: Vertical off set up or down can cause vehicles to lose control, cause tire damage, and vehicle damage. If the bridge is lower, then something failed and needs to have further investigation by SM&I

Action: Set up lane/road/bridge closures on both sides of bridge Notify SM&I and District TMC/EOC of a closed bridge Send any photos and information to SM&I Once it had been determined there is approach settlement and the bridge is safe, district crews can

place temporary AC ramps. Continue with the first assessment.

Open: AC ramp provides adequate access

Earthquake Response - Approaches

Close: Vertical offset of over 10 inches

Earthquake Response Columns: Multi-span bridges rely on the columns for support. Many older columns have been retrofitted with

steel shells. What to look for:

Railings or deck sagging greater than 3 inches (use best judgment as it could be an existing condition). Check for misalignment (vertical and horizontal) of the railings and abutment joints. Check to see if offset is over a pier or column. Check the pier or column for leaning. Look for any large diagonal cracks and/or spalled concrete in the columns. Exposed rebar deformation and broken concrete in the core

Concern: Shear cracks in old column designs causes the column to be very vulnerable to aftershocks and will have

reduced capacity The column maybe able to support its own weight but aftershocks and traffic can cause further damage or

collapse

Action: Set up lane/road/bridge closures on both sides Notify SM&I of a closed bridge Send any photos and information to SM&I

Earthquake Response Columns

Diagonal Cracks in Cover

Diagonal Cracks in Cover and in the core with bulging hoops – Close Bridge

Diagonal Cracks in Cover and column leaning – Close Bridge

High Load Assessment for Bridges

High Load Hits occur on State and Local agency bridges regularly. There is at least one high load hit per month that will result in lane closures and girder repair or replacement.

First Responder Duties:

Ensure the safety of the public on roads and bridges Rapid safety assessment for traffic damaged bridges Report to SM&I bridge condition information

First assessment will determine if the bridge or lane(s) need to be closed.

Questions to answer: Steel or concrete girders? Single or multiple girders damaged? A two girder or multi-girder bridge? Can the traffic be moved to an unaffected side? Does the traffic under the bridge need to be diverted? Does the bridge need to be closed?

High Load Assessment for Bridges

Possible actions: Set up a lane/road closure where necessary. May need CHP assistance. Remove any debris in the roadway. Clear any loose sections or debris on the bridge. Contact SM&I, send bridge question information, photos and what

actions have and will be done until the SM&I inspector arrives on scene.

How can you tell if the bridge needs to be closed for bridge types: Concrete Box girder bridge Reinforced concrete girder bridge Pre-stressed I beam bridge Two Steel girder bridge Multi girder steel bridge Steel Through truss bridge

Notify: SM&I Command Center, 1-888-893-9974, Email: smidcc@dot.ca.gov Structure Maintenance and Investigations, Sacramento Off:(916)227-8631, fax:(916)227-8357

What type of bridge was hit?

Questions when High Load Hits are reported: •Does the bridge need to be closed?

•Can the traffic be moved to the unaffected side? •Does the traffic under the bridge need to be diverted? •Are there multiple girders damaged? •Is there loose debris to be removed from the bridge? •Is there loose debris to be cleaned up on the road? •Contact SM&I with damage description.

Reinforced I Beams

Pre-stressed I Beams

Steel Girders

Concrete Most all concrete bridges have

multiple girders

Steel

Steel Through Truss

Broken main longitudinal rebar

Broken stirrup rebar(s) and no damage to stressing strands

Broken stressing cable(s)

Minor Damage to girder flange or web. No tears or cracks seen in steel from 24 inches. Out of plane twisting or movement less than 6 inches

Minor Damage: Only the cover concrete is damaged (no rebar damage): Remove loose material: Re-open the bridge. Recommend: clean and patch damaged area.

Medium to Heavy Damage

Bridge Traffic should be diverted off/around the damaged area. Lane closure underneath remains in place until SM&I inspects. Complete route closure may be needed.

Remove loose material: Re-open the bridge. Rec: Clean, repair rebar, and patch

Traffic on the Bridge should be diverted off/around the damaged area. Lane closure underneath remains in place until SM&I inspects.

Depending on how many girders are damaged will determine if traffic can be diverted.

Multi and two girder bridges will be treated differently when sustaining major damage

Multi-Girder Bridge

Two Girder Bridge

Bridge can be opened with no restrictions. Notify SM&I

Trusses are viewed as a two girder system

Minor Damage to truss members. No tears or cracks seen in steel from 24 inches. All Connections secure.

Major Damage to truss members: Tears or cracks seen in steel from 24 inches. Connections are sheared. Extreme out of plane bending will cause damage at connections. The major truss members can take a lot of damage before a complete bridge closure. Tears can propagate when in tension. Engineering judgment will be needed to reopen with extreme damage.

Bridge can be opened with no restrictions. Notify SM&I

Damage to wind bracing members will not reduce capacity or need lane closures. Remove or bend bracing back above minimum road clearances. Note: bracing damage can bend and/or tear vertical members.

Major Damage: Tears or cracks seen in flanges and/or web; Connections are sheared; Extreme out of plane bending. Hit induced notches or

sharp groves in the flanges may cause fatigue problems. Contact SM&I if found.

Divert bridge traffic to the undamaged side if possible. Notify SM&I

Close the bridge and divert traffic for routes under bridge until shoring is in place.

Minor Damage

Medium to Heavy Damage

Minor Damage

Medium to Heavy Damage

Minor Damage

High Load Hits

Concrete Girder Bridges: Pre-stressed Pre-cast I beams and Reinforced Cast-in-place girders

Pre-stressed I beams: Severe damage closing traffic both top and under routes

How Does SM&I Support the Districts

A SM&I Bridge liaison will be present at activated HQ DOC and all District EOCs.

Our response center will also be activated and ready to deploy our inspectors for any bridge emergency.

Provide Official bridge data and field conditions to the EOCs.

Provide technical bridge support for emergency bridge repairs, assessments, and emergency bridges to name a few.

How Does SM&I Support the Districts cont. SM&I can have 40 teams of inspectors ready to deploy

in hours SM&I has $2.3 million in emergency bridge parts and

can build several 200 to 250 foot emergency bridges Underwater inspection program with boats and divers Rope Access trained inspectors NDT Technicians levels 2 and 3 PE Civil engineers – NHI Certified Inspection Team

Leaders

Most recent Events Last month flash flooding closed I-10, San Bernadino

County on the way to Arizona South SM&I Inspection teams and North SM&I design

groups responded with inspection on all bridges in the area and fixes to keep the remaining bridges open.

Last week SM&I supported Cal-EOS by providing technical support emergency bridges in a remote location for fire crews to cross and fight the fire in Yolo County

Temporary Bridge Support SM&I was able to provide some guidance for access

across a closed county bridge. The National Guard station in Redding deployed their

Improved Ribbon Bridge (IRB) and was able to open in less than a day once on site.

SM&I now knows the capabilities and limitations of the IRB.

Cache Creek Bridge Zero Ton load rating, closed 2008

Opened at 0200 Hours (that’s 2am in the morning)

First Cal Fire truck at 0800 Hours (8 am in the morning)