A nonlinear finite element model is developed for the analysis of plain and reinforced concrete column confined by FRP sheets. The column sections chosen for the analysis are either circular or square in shape. The behavior of small and large scale FRP wrapped concrete columns under uni-axial compression is investigated using the developed model. The proposed FEA model is based on appropriate selection of elements, strength failure criteria and other parameters required for accurate analysis of concrete columns confined with FRP sheets. The model is validated with some published results on FEA and experimentation. A detail parametric study is done to quantify the effect of the thickness, stiffness and fiber orientation of the FRP sheets as well as unconfined concrete strength on confinement and stiffness of the strengthened columns using the proposed model. Based on the present analysis results, accurate stress distribution in concrete and FRP is also obtained which improves understanding of the confinement mechanism of the concrete columns.

Criteria weights formulation is the most essential component of a multi-criteria prioritization scheme. The research reported in this paper sought to critically compare a recently developed multi-criteria optimization criteria weights method to the well-known Analytic Hierarchy Process (AHP) as well as the method employed by the bridge management software BrM (formerly Pontis), which is licensed to all 50 State Departments of Transportation in the United States. Using four criteria for demonstration (bridge performance, utility, vulnerability to climate-triggered extreme events, and vulnerability to climate-triggered extreme loads), the new method clearly separates the concept of prioritization from the concept of optimization. The study demonstrates that there is an important and practical difference between a suitable criteria weight formulation for asset management optimization, on one hand, and the type of formulation required for a general selection problem, on the other hand. More importantly, the new method performs better than both the AHP and the BrM on all the important measures.

PurposeThe study investigates the performance of a three-story unprotected steel moment-resisting frame (SMRF) designed for high seismic demand in the fire-only (FO) and post-earthquake uniform and traveling fires (PEF). The primary objective is to investigate the effects of seismic residual deformation on the structure's performance in horizontally traveling fires. The traveling fire methodology, unlike conventional fire models, considers a spatially varying temperature environment.Design/methodology/approachMulti-step finite element simulations were carried out on undamaged and damaged frames to provide insight into the effects of the earthquake-initiated fires on the local and global behavior of SMRF. The earthquake simulations were conducted using nonlinear time history analysis, whereas the structure in the fire was investigated by sequential thermal-structural analysis procedure in ABAQUS. The frame was subjected to a suite of seven ground motions. In total, four horizontal traveling fire sizes were considered along with the Eurocode (EC) parametric fire for a comparison. The deformation history, axial force and moment variation in the critical beams and columns of affected compartments in the fire heating and cooling regimes were examined. The global structural performance in terms of inter-story drifts in FO and PEF scenarios was investigated.FindingsIt was observed that the larger traveling fires (25 and 48%) are more detrimental to the case study frame than the uniform EC parametric fire. Besides, no appreciable difference was observed in time and modes of failure of the structure in FO and PEF scenarios within the study's parameters.Originality/valueThe present study considers improved traveling fire methodology as an alternate design fire for the first time for the PEF performance of SMRF. The analysis results add to the much needed database on structures' performance in a wide range of fire scenarios.