Building Constructions 1. 3rd workshop exercise: structural floorplan 1. FLOORPLAN of the 1st FLOOR FLOORPLAN of the 1st FLOOR SECTION (vertical) of the 2 floors

The workshop exercise is about how to design a floorslab with prefabricated rc beams and filler blocks. You can find the different types of floor constructions on the BC1 website of the Department. We have chosen ”E-beam” type of slab for this w.e. Before starting planning it’s necessary to get familiar with the situation that has to be solved. What the load is and what the loadbearing structure is. Please check the two floorplans! We would like to design the slab above the 1st floor. So we can find the possible loadbearing elements on the 1st floor. The slab has to cover the 1st floor and give a floor for the 2nd one. You choose the bigger area to cover. In our situation the 2nd floor is bigger so the slab will be as big as the architectural floorplan of the 2nd floor. The loads will be the slab itself and the walls that are standing on it. If we would like to draw the structural floorplan above the 1st floor we cut the 1st floor 1m under(!) the ceiling and look UP! Please do not forget to draw the edge of the balconies, too, because you need a slab there as well. What do we indicate on a structural floorplan? Elements of the loadbearing system and the loads. 1. Loadbearing elements of the 1st floor:

- possible loadbearing walls (loadbearing walls and infill walls) - lintels

2. Elements of the slab construction (perfabricated beams, monolithic rc slabs, monolithic beams, ringbeam, flight of steps. 3. Loads (walls that are standing on the slab) 3. Edge of the openings in the slab (f.e. for shafts)

2.

Now we take our architectural floorplan (you can find it in 1:200 on the separate final str. floorplan sheet) and draw the possible loadbearing elements, the edge of the slabs, the edge of the openings in the slab and the load giving elements (partition walls) of the upper floor to start drawing the structural floorplan. Indications:

- possible loadberaing elements (thick walls): thick section lines beacuse we cut these structures

- edge of the slabs, edge of the openings in the slab: thin sight lines - the load giving elements (partition walls): thin dashed lines beacuse

they are in hidden position

possible loadbearing wall edge of the opening flight of steps edge of the balcony partition wall

3.

Next step is to check the critical points on the floorplan. We indicated a few examples on the floorplan, not all of them. 1. Spanning directions (load-bearing walls) (the shorter direction, but

influenced by the openings, balconies, cantilevers etc.) A beam has to be supported on the two ends by loadbearing walls. The spanning direction is paralel with the direction of the beams. The arrow shows in which direction the loads are transmitted. Rule: the shorter span is the better. But if there is a big opening in the loadbearing wall above which a huge monolithic lintel is needed it is better to choose the bigger span (if it is not longer than the max. length of the prrfab. beam). N.B.: Always check the way of the load! The self load of the slab (plus the load of the partition wall) is transmitted to the ends of the beam and there it must be given to the next loadbearing element (wall, lintel, horisontal beam, cantilever beam) that will transmit it to the next loadbearing element and that one to the next loadbearing element, etc. till it reaches the loadbearing soil.

2. Critical points (shafts, heavy partition walls, balconies etc.) Shaft: the beam shouldn’t go through the shaft so the beam can be put only to the side of it. Heavy partition: we consider a partion wall heavy if it is running paralel with the spanning direction and longer than 2/3 of the span. N.b.: the load of the wall won’t be given to several beams but only to one! We consider walls runnung perpendicular to the spanning direction and in the middle third of the span as ”heavy’ partitions because they give extra load to the beams on the place where the moment is the biggest.

3. Coordination of beams (according to the type of the used structure (beams and filler blocks) The building rules of the prefab. slab must be checked (max. total length, distance between two beams (we indicate the distance between the axis lines of them)

The 1st beam can basicly be right beside the wall. (N.b.: The distance between the edge line of the wall and the axis line of the beam is 7 cm in case of E-beam because the ’shoe’/lower part of the beam is 14 cm and the beam shouldn’t be laying on the wall so it shouldn’t be supported on the long side.). But usually it is recommended to position the first beams at the critical parts because we will have less ’overleft’ monolithic slabs in that way.

4. Monolithic slabs (the rest part of the slab next to the prefabricated beams, around the shaft, balconies etc.) Where can’t put prefabricated beams we put a monolithic rc slab. N.B.: A mon. rv slab has a spanning direction!!! It must be supported on two opposite sides. It can be supoorted by a wall or an edge of an rc slab but not by an opening in the slab!

5. Lintels (monolithic or prefabricated) It is generally more practical to use prefabricated ones but if the opening is too long (bigger than the max. span of the pref. lintel) or the lintel gets too big load a monolithic lintel is the good choice.

6. Ringbeam, monolithic beams and bracing ribs depending on the spanning distance Please remember the 2nd workshop exercise where we checked the ”lintel and ringbeam” solutions. N.b.: Thermal insulation is needed in front of the rc ringbeam (it can be part of a ringbeam unit) and the vertical line of the thermal insulation in front of the ringbeam and in front of the lintels or between the lintels must be continous. (We indicate the edge of the ringbeam with thin dashed line beacuse it is in hidden positiion.) If a prefabricated beam is not strong enough to support a heavy wall or if we need a support for the flight of steps or we need a support for a balcony we use mon. rc beams. A crosswise running bracing rib is usually required above 4 m span.

4. After all we can start planning our slab construction! We won’t explain and solve the problem of the balconies because that will be the topic of the next w.e. but will indicate the chosen solution to see a completed structural floorplan at the end. Let’s take the floorplan with the possible loadbearing elements, the edge of the slab, edge of the openings and let’s find the proper spanning directions!

5.

As the next building step we think over where to put prefabricated lintels where monoltihic ones. We can leave the questionable parts empty. N.B.: We must recheck the lintels after solving the problem of the balconies. The edge of the ringbeam can also be indicated.

6.

Next step is the arrangement of the beams. We put double beam (3 beams) under heavy partition walls. We put 2(3) beams beside a wide opening (for a shaft) because big load will be given to the edge of the prefabricated slab (edge beams) from the moolthic rc slabs that are on the two sides of the opening. We use double beam and filler block structure where we need stronger slab because of having several partition walls on the area.

7.

Whereever we can’t put prefabricated beams we fill the gap with a monolithic slab. Don’t forget the spanning directions and to give support to these slabs too! (The ”whole” in the slab won’t support the mon. rc slab. And if you don’t give spanning direction and support to these slabs we will consider it as a not solved part in the semester project or test.) Remark: the red edge line is just to show the area of the mon. slab, it is not part of the final drawing. A monolithoc element is always shown just with the crossing line and the circle for its sign.

8.

Next step is to check where we need bracing rib (concreted part instead of one row of filler blocks) because of the span. N.b.: The balconies and the lintels connected to them is not solved for the moment (you will get info about it in the next w.e.)

9.

As a final step we have to give sizes, placing levels, signs, number of pieces of elements, lower level of the slab on the plan. Every information has to be given to know about every element what it is, how big it is, where it has to be placed, how many we need of it. Please find the final structural floorplan in a separate file!