An-Najah Staff

In  recent  years,  the  employment  of  computer  techniques  in  engineering  design  work  has  become  an  irreversible  trend.  This  is  achieved  through  using  computer  as  the  tool  for  modeling,  analysis,  and  design.  The  objective  of  this  paper  is  to  determine  the  stress  in  unreinforced concrete portal frame and predict  the cracks which will occur  in  the beam and  columns  in  this  frame  due  to  this  stress.  To  do  this,  a  technique  utilizing  finite  element  analysis  is used  in order  to create computerized model using  shell elements with SAP2000  program. This model  is  built  to  simulate  the  real  state  of  beam  and  columns  in  the  frame  under different loading conditions.

In recent years, the employment of computer techniques in engineering design work has become an irreversible trend. This is achieved through using computer as the tool for modeling, analysis, and design. The objective of this paper is to determine the stress in unreinforced concrete portal frame and predict the cracks which will occur in the beam and columns in this frame due to this stress. To do this, a technique is utilizing finite element analysis is used in order to create computerized model using shell elements with SAP2000 program. This model is built to simulate the real state of beam and columns in the frame under different loading conditions.

In the current practice, no special measures are applied for enhancing structural fire safety of steel bridge girders. Further, there is very limited information and research data in the literature on the fire resistance of structural members in bridges. In this paper the fire response of a steel bridge girder under different conditions is evaluated using the finite element computer program ANSYS. In the analysis, the critical factors that influence fire resistance, namely fire scenario, fire insulation and composite action arising from steel‐concrete interaction is accounted for. Results from numerical studies show that the composite action arising from steel girder‐concrete slab interaction significantly enhances the structural performance (and fire resistance) of a steel bridge girder under fire conditions. Other significant factors that influence fire resistance of steel bridge girder are fire insulation and type of fire scenarios.

For evaluating fire resistance of a reinforced concrete member, temperature profile in the cross section of the member is required. Current simplified approaches and design graphs do not yield reliable temperature predictions in rebar and concrete. In this paper, a simplified approach is proposed for evaluating cross-sectional temperatures in fire-exposed reinforced concrete members. The approach is derived through statistical nonlinear regression analysis, utilizing data generated from finite element analysis. The parameters that were varied in the finite element analysis include sectional geometry, concrete characteristics and fire exposure conditions. The validity of the approach for different types of concrete is established by comparing predictions from the proposed equation with data from fire tests and finite element analysis. Through these comparisons it is shown that the proposed equation gives better predictions of temperatures in reinforced concrete members. The applicability of the proposed approach in design situations is illustrated though a numerical example. The simplicity of the proposed method makes it attractive for use in design situations and for incorporation in design standards.