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American Society for Testing and Materials

Fire response of concrete structural members is dependent on the thermal, mechanical, and deformation properties of concrete. These properties vary significantly with temperature and also depend on the composition and characteristics of concrete batch mix as well as heating rate and other environmental conditions. In this chapter, the key characteristics of concrete are outlined. The various properties that influence fire resistance performance, together with the role of these properties on fire resistance, are discussed. The variation of thermal, mechanical, deformation, and spalling properties with temperature for different types of concrete are presented.

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Properties of Concrete at Elevated Temperatures

Comparison of compressive and splitting tensile strength of high-strength concrete with and without polypropylene fibers heated to high temperatures

Hydrothermal model for predicting fire-induced spalling in concrete structural systems

A numerical model, in the form of a computer program, for tracing the behavior of reinforced concrete (RC) beams exposed to fire is presented. The three stages associated with the numerical procedure for evaluating fire resistance of RC beams; namely, fire temperature calculation, thermal analysis and strength analysis, are explained. A simplified approach to account for spalling under fire conditions is incorporated into the model. The use of the computer program for tracing the response of RC beams from the initial pre-loading stage to collapse stage, due to the combined effect of fire and loading, is demonstrated. The validity of the numerical model is established by comparing the predictions from the computer program with results from full-scale fire resistance tests. Through the results of numerical study, it is shown that the type of failure criterion has significant influence on predicting the fire resistance of RC beams.

A numerical model for predicting the fire resistance of reinforced concrete beams

Abstract—The vast majority of the Middle East countries are prone to earthquakes. Despite that and from a seismic hazard point of view, the higher values of the superimposed dead load intensity of partitions and wearing materials of the constructed reinforced concrete slabs in these countries can increase the earthquake vulnerability of the structures. The primary objective of this paper is to investigate the effect of reducing superimposed dead load on the lateral seismic deformations of structures, the inter-story drifts and the seismic pounding damages. The study utilizes a group of three reinforced concrete structures at three different site conditions. These structures are assumed to be constructed in Nablus city of Palestine, and having superimposed dead load value as 1 kN/m2, 3 kN/m2, and 5 kN/m, respectively. SAP2000 program, Version 18.1.1, is used to perform the response spectrum analysis to obtain the potential lateral seismic deformations of the studied models. Amazingly, the study points that, at the same site, superimposed dead load has a minor effect on the lateral deflections of the models. This, however, promotes the hypothesis that buildings failed during earthquakes mainly because they were not designed appropriately against gravity loads.

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The Effect of Reducing Superimposed Dead Load on the Lateral Seismic Deformations of Structures

The evaluation of the pavement preservation interventions is the most important component of pavement maintenance management. There is a need for a rational methodology to evaluate pavement preservation alternatives to maximize both project and network level benefits. Lack of adequate guidance on the timings of preventive maintenance treatments was the main motivation for this study. Based on different effectiveness criteria, mathematical models to estimate optimum timing (OT) of maintenance treatments are developed to alleviate surface rutting. The Area2T model based on the long-term benefits was found to be a rational and a practical tool to estimate OT for various maintenance treatments by adjusting its parameters. The sensitivity and practical usage of the models are demonstrated by using the SPS-3 pavements in the paper. While the modeling approach uses the existing understanding, the model can be used to estimate OT of a fix based on the pre-treatment pavement performance, jump and slope adjustment factors for various treatment types. The required data for the model can be obtained for various treatments from the existing historical performance data collected for pavement management purposes. The results show that slurry and chip seals can be applied on younger pavements when rutting is minimal. However, thin overlays applications on older pavements with higher levels of rutting will maximize the long-term benefits.

Monther B. Dwaikat

Papers

The Effect of Reducing Superimposed Dead Load on the Lateral Seismic Deformations of Structures

Estimating Optimum Timings for Maintenance Treatments to Alleviate Pavement Surface Rutting

Closure to “Response of Restrained Concrete Beams under Design Fire Exposure” by M. B. Dwaikat and V. K. R. Kodur