Progressive collapse refers to a phenomenon, in which local damage in a primary structural component leads to total or partial structural system failure, without any…
Abstract
Purpose
Progressive collapse refers to a phenomenon, in which local damage in a primary structural component leads to total or partial structural system failure, without any proportionality between the initial and final damage. Robustness is a measure that demonstrates the strength of a structure to resist progressive collapse. Static pushdown and nonlinear dynamic analysis were two main procedures to calculate the capacity of structures to resist progressive collapse. According to previous works, static analysis would lead to inaccurate results. Meanwhile, capacity analysis by dynamic analysis needs several reruns and encountering numerical instability is inevitable. The purpose of this paper is to present the formulation of a solution procedure to determine robustness of steel moment resisting frames, using plastic limit analysis (PLA).
Design/methodology/approach
This formulation utilizes simplex optimization to solve the problem. Static pushdown and incremental dynamic methods are used for verification.
Findings
The results obtained from PLA have good agreement with incremental analysis results. While incremental dynamic analysis is a very demanding method, PLA can be utilized as an alternative method.
Originality/value
The formulation of progressive collapse resistance of steel moment frames by means of PLA is not proposed in previous research works.
Details
Keywords
The purpose of this paper is to recover the deficiency of existing tie force (TF) methods by considering the decrease in section strength due to cracking and by selecting limit…
Abstract
Purpose
The purpose of this paper is to recover the deficiency of existing tie force (TF) methods by considering the decrease in section strength due to cracking and by selecting limit state of collapse according to section properties.
Design/methodology/approach
A substructure is selected by isolating the connected beams from the entire structure. For interior joints, the TFs in the orthogonal beams are obtained by catenary action. For corner joints, the TFs are assessed by beam action. For edge joints, however, the resistance is gained by greater of the resistance under catenary action for periphery beams and beam action for all the connecting beams in both directions. For catenary action, the TF capacities must satisfy Equation (20). On the other hand, for beam action, the TF must satisfy Equation (16), while R is calculated from Equation (17). In the case where the length of the connecting beams is similar, Equation (19) can be used.
Findings
Closed form solutions are available for TFs on both beam and catenary stages.
Originality/value
The proposed formulation makes designing more practical and convenient. However, the proposed formulation had good agreement with experimental results.