Structural engineering design generally involves the assessment of loads and their effect on a member and providing the right size and position of the member(s) to cope with the applied loads.

In the next few days (and probably weeks), I'll be discussing structural design in simple step-by-step guidelines to assist young structural engineers as well as other built environment professionals that may find the information useful.

Today I'll be looking at Slabs.

Slabs are structural elements that support loads by flexure (bending) and are relatively thin when compared to it's surface area. Slabs can be either be 1. On-grade or 2. Suspended.
Slab on grade is when it is placed on a base (mostly on the ground) and in buildings it is the over site concrete (also referred to as dpc)

Suspended slabs are supported by beams or walls and may span either one-way or two-way. The span measures the distance between supports.
One way span simply means the slab has 2 supports (opposite each other) while 2-way has 4 supports. However, in a 2-way spanning slab, if the long side (ly) is more than twice short side (lx), then the slab should be considered as spanning 1-way in the shorter direction.

Will continue tomorrow on loading and sizing of suspended floor slab.

Regards

following.

It will be nice if you add pictures

Pictures will accompany next post

Yesterday, we started looking at floor slabs. Today, I'll continue with types of suspended floor slabs commonly used in construction here in Nigeria.
1. Solid slabs - the most common type and comprises a thick section of concrete (usually between 100 - 200mm thick, 150mm most used).
Spans can be as small as 1m and as large as 5-6m with beams/walls as support.
2. Ribbed slabs - this comprises concrete ribs and flanges and spaced about 0.4 - 0.7m apart. It is most suitable when long spans are required without having excessive dead loads from self weight. Ribbed slabs span 1-way.
3. Flat slabs - this form of slab does not have any supporting beams as the slab rests on the columns directly. Reinforcement quantities are a bit high but it offers the advantage of speedy construction and better partitioning
4. Waffle slab - this is similar to the ribbed slab but with the ribs spanning in two directions i.e. 2-way.

Tomorrow, we'll be looking at design steps for solid slabs.

All the best.

southniyikaye:
It will be nice if you add pictures

1. For the section through the ground, notice that the slab is firmly supported on the prepared base. In fact , the strength /capacity of the ground slab is dependent on how firm and solid the prepared base is.
2. On the 1st floor layout drawing, almost all the slabs span 2-way. However, the panel on grid E-F/1B-3 Spans 1-way even though it is supported on four sides. Why? Well, the ly/lx ratio is significantly greater than 2

Good morning.

Briefly, we'll be looking at steps in the design of solid floor slab.
Loading: Mainly dead loads (DL) and imposed or live loads (LL). Dead loads are permanent and fixed loads like self weight, finishes and fixed partitions etc. Live loads are movable and transient and depends on the use of the floor under consideration. While DLs are calculated, LLs are obtained from a load table ( Structural Designers Manual or Handbook)

The calculated loads are factored (for safety) and summed and a design load obtained; n = 1.4gk + 1.6qk where 1.4 is the safety factor applied to dead loads (gk) and 1.6 to live loads (qk)

Depending on whether the slab spans 1-way or 2-way and also the support conditions, bending moments (BMs) and shear forces (SFs) are calculated.

Series continues tomorrow. ..

Good job[color=#000099][/color]

op. we are still waiting for updates please.

itavista:
Good morning.

Briefly, we'll be looking at steps in the design of solid floor slab.
Loading: Mainly dead loads (DL) and imposed or live loads (LL). Dead loads are permanent and fixed loads like self weight, finishes and fixed partitions etc. Live loads are movable and transient and depends on the use of the floor under consideration. While DLs are calculated, LLs are obtained from a load table ( Structural Designers Manual or Handbook)

The calculated loads are factored (for safety) and summed and a design load obtained; n = 1.4gk + 1.6qk where 1.4 is the safety factor applied to dead loads (gk) and 1.6 to live loads (qk)

Depending on whether the slab spans 1-way or 2-way and also the support conditions, bending moments (BMs) and shear forces (SFs) are calculated.

Series continues tomorrow. ..

good job