Concrete, as a complex and anisotropic material, poses challenges in accurately simulating its behavior in numerical simulations. This paper focuses on selecting an appropriate constitutive model for simulating the behavior of a steel–concrete composite column using finite element analysis under compression and push-out tests. Two models are analyzed and compared, namely, Drucker–Prager and concrete damage plasticity. The results demonstrate that the concrete damage plasticity model outperforms the Drucker–Prager model in all six test cases, indicating its superior accuracy in capturing the composite column’s behavior. This study enhances the reliability of numerical simulations for steel–concrete composite structures by choosing the most suitable constitutive model, parallel with extensive sensitivity analysis and model calibration. The findings emphasize the significance of meticulous model selection and precise parameter definition for achieving accurate predictions of concrete behavior. This research contributes to advancing the understanding and modeling of concrete’s intricate behavior in structural analyses.

Flat plate–voided concrete slab systems, which have been used for many years in Europe and other parts of the world, are becoming increasingly popular in the United States because of their many inherent benefits. Such benefits include reduced weight, which results in smaller seismic forces and larger superimposed loads for given span lengths; economical longer spans; reduced floor-to-floor heights; accelerated construction schedules; and inherent fire resistance that meets the fire-rating requirements of the International Building Code (IBC). This paper presents (1) the history and recent research on flat plate–voided concrete slab systems, (2) flexural and shear strength design requirements, (3) deflection requirements, (4) vibration criteria for human comfort and sensitive equipment, (5) fire-rating requirements in accordance with the IBC, (6) typical installation sequences, and (7) a summary of the main benefits of flat plate–voided concrete slab systems. The paper shows that such systems can be designed using the provisions of the American Concrete Institute (ACI) for strength and serviceability and can satisfy the minimum requirements for vibration control and fire resistance.

Purpose: Heavy hex structural bolts have been used in a wide range of steel structures for many years. However, these structures remain susceptible to fire damage. Conducting fire experiments on full-scale steel structures is costly and requires specialized equipment. The main purpose of this research is to test, analyze and predict the behavior of ASTM A325 bolts under tension loading in simulated fire conditions and develop a reliable finite element model that can predict the response of similar bolts without the need for repeated testing.Design/methodology/approach: The experimental work was conducted at the University of Wisconsin-Milwaukee, where an electric furnace was custom-built to test a bolted specimen in tension under elevated temperatures. A transient-state testing method was adopted to perform a group of tests on 12.7 mm (½”) – diameter A325 bolts. The tests were divided into two groups: the first one was used to calibrate the equipment and choose a final testing arrangement and the second group, consisting of four identical tests, was used to validate a finite element model.Findings: The temperature-displacement and load-displacement response was recorded. The tested bolts exhibited a ductile fracture in which a cup-and-cone shaped failure surface was formed in the threaded section at the root of the nut. ASTM A325 bolts are widely used by engineers in building and bridge construction, the results of this research enable engineers to determine the behavior and strength of ASTM A325 bolts when such bolts when exposed to fire event.Research limitations/implications: Structural bolts are used to connect structural members, and they are part of structural assembly. To study the behavior of the bolts, the bolts only were investigated in a fire simulated in a furnace. The bolts studied were not part of a structural assembly.Practical implications: The results of this study enable engineers to evaluate the condition of ASTM A325 bolts when subjected to fire loading.Originality value: Tests were conducted at the University of Wisconsin – Milwaukee’s structures laboratory to study the effect of fire on an ASTM A325 bolts. Many tests under fire loading have been performed by researchers on different components of steel structures, this study focuses on studying the behavior of ASTM A325 bolts which are widely used in the USA.

Purpose: The purpose of this paper is to present the effect of damaged fireproofing on structural steel members. This study will show that a minor damage in fireproofing will reduce the fire rating of members significantly. Damaged fireproofing happens in structures due to various reasons, and the question is always how effective is this fireproofing? This paper presents the results of one type of fireproofing and presents a parametric study on the size of damage and its effect on fire resistance of structural steel members. Design/methodology/approach: The study has been performed using numerical methods, thermal and structural finite element analysis. The analysis method has been verified by experimental results. Findings: Small fire protection damage or loss leads to significant rise of temperature at the damaged parts and causes severe fire resistance reduction of beams. The higher fire protection damage’s extension at the bottom flange of the steel beams does not have any major influence on the rate of reduction of fire resistance of the beams. Steel beams experience greater fire resistance reduction at higher load levels because of the existing of higher stresses and loads within the steel beam section. Research limitations/implications: The study has been performed using finite element analysis, and it covers a wide range of practical sizes. However, experimental work will be performed by the researchers when funding is granted. Practical implications: The study provides researchers and practitioners with an estimate on the effect of damaged fireproofing on fire resistance of structural steel beams. Social implications: Understanding the effect of the effect of damaged fireproofing helps in estimating the fire resistance of structural steel members, which may protect collapses and disasters. Originality/value: The research is original; extensive literature review has been performed, and this research is original.

The dynamic response of a machine-foundation system depends on several factors, such as (1) the soil dynamic properties, (2) geometric properties of the foundation, (3) amplitude of the applied dynamic loads, and (4) frequency of the dynamic excitation force. The main goal in machine foundation design is to keep the foundation response within a specific limit to enable the satisfactory operation of the machine. If the foundation response exceeds this limit, the foundation will adversely affect the performance of the machine and may damage the machine internals or cause it to function improperly. Furthermore, the excessive vibrations impose additional stresses on the machine resulting in increased unbalanced loading, and thus, to increased dynamic loads on the soil-foundation system. This paper presents the results of the dynamic analysis of a four-cylinder compressor foundation. The original design of the foundation was performed in the early 1960s and ignored the effect of the soil on the response of the foundation system; therefore, the foundation has been suffering from excessive loading. The foundation block supported a four-cylinder compressor, suction and discharge bottles, and a crank and driving motor with a total weight of approximately 974 kN (219 kips). The results of a three-dimensional (3D) finite-element model of a soil-foundation system was used to determine the dynamic response of the soil-foundation system and to assess the foundation response under applied dynamic loading resulting from the compressor crank. The dynamic analysis was performed by performing (1) eigenvalue analysis of the foundation block, considering the effect of the soil-foundation interaction, to determine the soil-foundation natural frequencies and modal participation factors and (2) a forced response of the foundation under an unbalanced crankshaft load applied to determine the forced response amplitude of the soil-foundation system.