RCD QUIZ 2

Strength Design Method

Primary method used in the National Structural Code of the Philippines (NSCP) 2015 for designing reinforced concrete structures.

Strength Design Method

This method focuses on ensuring the design strength of a structural member is greater than or equal to the strength required to resist factored loads

Strength Design Method

Method of proportioning and designing structural members such that the computed forces produced in the members by the factored loads do not exceed the member design strength.

Nominal strength

Strength based on dimension and material property

Required Strength

This is the load effect on the structure, calculated by applying load factors to the service loads (dead load, live load, wind load, etc.).

Reduction Factor

This factor is less than 1 and accounts for uncertainties in material properties, construction quality, and analysis methods.

Allowable Stress Design

Maximum stress a material or structure can withstand under normal operating conditions without failing

Allowable Stress Design

It involves calculating stresses caused by service loads and comparing them to allowable stresses, which are derived from material strength and incorporate a factor of safety

Allowable Stress Design

Method of proportioning and designing structural members such that elastically computed stresses produced in the members by nominal loads do not exceed specified allowable stresses.

Loads

Forces or other actions that result from the weight of all building materials, occupants and their possessions, environmental effects, differential movements and restrained dimensional changes

0.003

Maximum strain at the extreme concrete compression fiber, εc = _

On Strain

Plane sections remain plane; strain varies linearly from the maximum compressive strain at top fiber to the tensile strain at bottom reinforcement.

On Stress

Stress on beams is represented by a parabloc distribution along the compression zone.

Nominal Moment Capacity or Nominal Flexural Strength

Maximum bending moment without any safety factors

Ultimate Moment Capacity

Maximum bending moment with safety factors; Moment Due to Factored Loads; Factored Design Moment; Design Strength

Strength Reduction Factor

A coefficient used to provide a margin of safety in Ultimate Strength Design

Coefficient of Resistance

A coefficient used to relate the member's capacity with its geometric properties or dimensions

Steel Ratio

the proportion of tension reinforcement to the effective concrete area ; ensures balance on steel reinforcement against the effective area of beam

Steel Ratio

It is a critical parameter that determines the structural behavior, strength, and failure mode of a member. It balances the concrete's compressive strength with steel's tensile strength, ensuring that structures are safe, durable, and economical.

Balanced condition

The maximum strain at the extreme concrete compression fiber just reaches the crushing strain εc= 0.003 at the same time as the tension steel reaches a strain εs= fy / Es causing them to fail simultaneously.

Compression controlled

Concrete may fail before the yield of steel due to the presence of high percentage of steel in the section more than what is required for balanced condition. In this case, the concrete strength and its maximum strain of 0.003 are reached, but the steel stress is less than the yield strength, that is fs < fy. The strain in the steel is equal to or less than 0.002.

(Overreinforced)

Tension controlled

Steel may reach its yield strength before the concrete reaches its maximum strength, in this case,the failure is due to the yielding of steel reaching a high strain equal to or greater than 0.005. The section contains a relatively small amount of steel lesser than what is required for balanced condition.

(Underreinforced)