The three most common materials from which most structures are built of wood, steel, and reinforced concrete. Reinforced concrete is unique among the three in that two materials. Reinforcing and concrete are used together, thus the principles governing the structural design differ in many ways from those involving design in one material.
Reinforced concrete design encompasses the fundamental principles in the design & investigation of reinforced concrete subjected to:
a. Axial Force
b. Bending Moments
or the combination of the above
Although analysis in design may be treated separately, they are inseparable in practice, especially in a statical indeterminate structure wherein preliminary estimates of the size of members are required and then checked for conformance with stability, compatibility, and safeness.
Steel rebar and concrete work readily for many reasons:
a. Bond (Interaction between the rebars and surrounding hardened concrete) prevents slip of rebars relative to the concrete.
b. Proper concrete mixes provide adequate impermeability of concrete against bar corrosion.
c. Sufficient similar rates of thermal expansion introduce negligible stresses between steel and concrete under temperature changes.
1. Reinforced Concrete (rebars concrete)
a. Aggregate (70% – 75%)
– Free from impurities
a.1 Sand – fine aggregate
– Passing No. 4 Sieve
a.2 Gravel – course aggregate
– To have plasticity and fluidity
Here is the meaning of concrete.
Concrete – is a stonelike material obtained by permuting a carefully proportioned mixture of cement, sand, and gravel or other aggregates, and water to harden in forms of the shape and dimensions of the desired structures.
2. Design Basics
a. Strength (safety)
A. Dead Loads
Are the ones that are constant in magnitude and set in location throughout the duration of the structure. Usually, the major area of the dead weight is the weight of the structure itself.
B. Live Loads
Consist chiefly of occupancy loads in buildings, and traffic loads on bridges. .They maybe either or completely in place or not present whatsoever partially. And could also change in location, their magnitude and distribution at any moment are uncertain and even their maximum insets throughout the duration of the framework aren’t known with precision.
C. Environmental Loads
Consist mainly of blowing wind pressure and suction earthquake loads and snow load Example: Inertia forces triggered by earthquake motions, soil stresses on subsurface portions of structures, loads from possible ponding of rainwater on flat surface types and forms triggered by temperature differentials. Like live loads and environmental loads at any moment are uncertain both in magnitude and distribution.