Hussam K. Risan

• Professor in Structural Engineering
• Professor (Full) at Nahrain University

Despite previous efforts to detect concentrated stresses in structures with holes, a complete understanding of structures that contain compound openings in addition to screw holes in critical stress areas is incomplete, especially for structures that are subject to sudden collapse. This study aims to conduct a laboratory test program to simulate a...

The prestressed members of a post-tensioned cable are classified as either bonded or unbonded according to the tendon bonding conditions. Trials and research that interested in a discrepancy between bonded and unbonded of different kinds of prestressed concrete members were rarely reported. This investigation aims to carry out a statistical compari...

The effect of prestress force value on the dynamic characteristic members dynamic characteristics been excessively argued among researchers till now. This study aims to perform a statistical method based on a meta-analysis investigating the influence of prestressing force on the first mode shape natural frequency of a prestressed reinforced concret...

Silos are strategical structures used to stockpile various types of granular materials. They are highly vulnerable to earthquake excitation and have been frequently reported to fail at a higher rate than any other industrial structure. The seismic response of silos within the near-fault region will suffer a complex combination of loadings due to th...

Water tanks represent an important critical structure type for the provision of water necessary for continuation of life and firefighting purposes. The objective of this paper is to study the response of reinforced concrete rectangular tank on grade in the presence of cleanout hole under the effect of an earthquake. This numerical analysis was cond...

The ACI code and ASTM specifications draw a clear road map on how to assess the deterioration of existing concrete structures. Yet, imperfect application of the road map and testing procedures may result in confused, inaccurate and costly outcomes. This field study covered a procedural assessment of an existing concrete structure starting with visu...

Pre-stressed members in various structures are gaining popularity among engineers in many parts of the world because pre-stressed strands offer better stability, serviceability, economy, aesthetics, and structural efficiency. The profile of the strand greatly influences the tensile strength of concrete. The force exerted by the strand on the concre...

The purpose of this study was to conduct a meta-analysis that shows the influence of fiber on ultimate compressive strength and tensile strength of ultra-high performance concrete. The internet scholarly search engines and ScienceDirect article references were used to illustrate the papers concerning the experimental investigations of mechanical pr...

In most vibration structural problems, the value of damping is less than unity. Such a small amount of damping may increase near or exceed unity under certain special circumstances. Critically damped and overdamped solutions are completed until the final expressions are generated and an indication provided by MATLAB as to how these expressions depe...

Near-fault ground motion can be identified by the presence of a predominant long duration pulse in the velocity traces mainly due to directivity effect. This pulse exposes the structure to high input energy at the beginning of the earthquake which leads to a higher response in comparison with the ordinary ground motions. This paper investigates 79...

This study present a numerical analysis corbels cast with high and normal strength reinforced concrete strengthen with Carbon Fiber Reinforced Polymers (CFRP) strips in different pattern ways. Twenty-two corbel specimens are a simulation in ABAQUS software program and all specimens tested under monotonic loading. Two specimens' normal and high stre...

Abstract: In spite of the plastic behavior of structure is not often allowed under continuous operating conditions it is quite fit for design when the structure is under loading that only occur a few times during its life. The object of this study is to investigate the response of elasto-plastic SDOF structures subjected to blast loading with diffe...

A numerical analysis of simply supported square slabs with square central opening strengthened by Carbon Fiber Reinforced Polymers (CFRP) attached to its four corners in a skew pattern has been present in this paper. The slab was tested by other under uniformly distributed load up to failure. The aim of this work is to obtain knowledge concerning t...

Gumbel’s theory of extreme value distributions has been often used in the statistical forecasting of maximum earthquakes magnitude occurrence. The basic working theory behind this method is based on assumption that observations distributions of earthquake risks follow either type I (Gumbel) or Type III (reflected weibull). In certain cases, however...

In spite of the plastic behavior of structure is not often allowed under continuous operating conditions it is quite fit for design when the structure is under loadng that only occur a few times during its life. The object of this study is to investigate the response of elasto-plastic SDOF structures subjected to blast loading with different TNT qu...

The repetition of earthquake ground motion of medium and strong intensities at brief time intervals has been often observed and interested recently. In this work, the influences of successive earthquakes on the response of purely elastic and elasto-plastic SDOF structure are analyzed. An extensive parametric study for SDOF structure under repeated...

Numerical analysis of the central hole in RC walls with and without CFRP, subjected to uniform eccentric vertical line load, is presented in this paper. Six half-scale wall panels were modelled using the ABAQUS software to estimate the strengthening effects. The analysis revealed that the load capacity of the wall in terms of maximum load carrying...

In this study attempt made to asset the strength of normal and high quality strength concrete with embedded reinforcement bars in two locations and directions using ultrasonic pulse velocity and equivalent core test. Reinforcement bars are always too dense with small spacing in reinforced concrete structures. Any semi or nondestructive test by core...

Action of applied external loads, early thermal by hydration of cement in reinforced concrete (RC) structures, creep and shrinkage and seasonal effects due to environmental conditions are the main causes of inducing cracks in RC members. Most Design Codes of RC structures have underestimated the distribution steel requirements based on stating nomi...

Openings in reinforced concrete (RC) slabs are usually created as a result of variations in construction function, architectural or mechanical necessities. Heavy equipment loads resulting from mechanical system of any building are often carried by RC slabs. Even the static analysis and design of RC slabs with opening is not clearly stated in the av...

The performance of structures under normal service loads refer to serviceability limit states which is concerned with the uses and occupancy of structures. The magnitude of deflections is the main considering of serviceability. In the present study, the finite element method was used to find the instantaneous deflection of reinforced concrete two-w...

Reinforced concrete (RC) slabs on elastic foundation are frequently subjected to heavy equipment loads due to mechanical system that required serving the building. In this study, the analytical solution of such problem with simply supported boundary condition was achieved by using double Fourier sine series. On other hand, a numerical solution base...

The purpose of this study was to conduct a meta-analysis that shows the influence of fiber on ultimate compressive strength and tensile strength of ultra-high performance concrete. The internet scholarly search engines and ScienceDirect article references were used to illustrate the papers concerning the experimental investigations of mechanical pr...

Analytical solutions for structures with opening were only derived for limited domains with very simple geometry. Although the finite element method (FEM) computes accurately the displacements, it is ineffective in determining the stresses in area of large stress gradients. The boundary element method (BEM) has been adopted in this paper which is w...

A study has been made through this investigation to understand the behavior of UHPC members with steel fibers by using two approaches: experimental investigation of concrete mixes and simulation of the problem studied by other researchers using finite elements. Experimental investigation is carried out to obtain the mechanical properties for two ty...