Assignment about Medium Rise Structures

Introduction
Medium rise structures refers to buildings which do not exceed six storeys. When designing such
structures, the effects of wind loads and earthquakes are ignored during the design.
The loads on the structure are derived from the weight of the materials used, occupants, point
loads and accidental loads. In order to safely carry the loads, the components of the structure
must be designed as per guidelines in the engineering codes used. The components of the
structure and transfer of loads is discussed below.
Footing system
1. Pile footing.
The foundation is made up of slender columns made up of reinforced concrete extending
through the soil to regions with adequate bearing capacity. The reinforced concrete used
in the slender columns are used to hold the structure in place and transfer the load to
deeper regions by either skin friction or end bearing.
This type of footing is used where the soil’s shallow depth has low bearing capacity, not
able to resist uplift and not fit to resist extreme settlement. Pile footing is appropriate
when:
 Soil at shallow depth is compressible.
 Probability of scouring is high due to closeness to seashore or other water bodies.
 When construction is done close to a deep drainage system or canal.
 Water level is high.
 There is poor soil conditions making it impossible to excavate.
 There is heavy inflow of seepage making the foundation trenches overflown all
the time.
2. Section through a pile footing.

Figure 1: Section through a pile footing.
3. Section through retaining wall.

Structural system
1. Diagram showing how a frame supports the load of the building.
A system responsible for carrying loads from one component of the structure to another
results to a continuous path throughout the structure. The system is as follows:
 The floor slabs carry the loads imposed on the floor of each storey. The loads
include self-loads, surface loads, linear loads and point loads.
 The beams carry loads transmitted to them by the slabs as well as their own
weight. They also carry loads of the walls installed on them.
 The beam loads are carried by the column. The column transfers this loads to the
foundation.

 The loads from the columns are carried by footings (foundation). The footings
transfers the loads to the ground.
Figure 2: Load path from the slab of the structure to the bearing soil/rock.
2. Types of connections between structural members.
Beam to floors
Floors/slabs transfer the loads to beams. Therefore, slabs ensure that all the loads
imposed on it are safely transferred to the beams. The slabs also distribute loads across
them thus avoiding cumulating of stress at one point (Comodromos, 2009).
Columns to beams
Beams transfer loads to columns. The columns are placed at intervals large enough to
accommodate the accumulating loads in beams.
Footings to columns
Columns ensures that all the loads it carries are safely transferred to the foundation
(footing). The foundation then transfers the loads to the ground.