Asian journal of civil engineering
Volume:17 Issue: 1, Feb 2016

Traditionally design of concrete will be a function of strength and not as a function of durability. To meet the requirements of durability in addition to strength, high performance concrete was developed. In this paper a detailed experimental investigation was carried out to evaluate the mechanical and durability characteristics of high performance fiber reinforced concrete to understand the effect of fibers. Experiments were conducted for three different water-binder ratios of 0.225, 0.25 and 0.275. Similarly three different volumes of fiber namely 1, 1.5 and 2% of volume of concrete were used. The characteristic compressive strength of concrete was taken as 70 MPa. Properties such as compressive strength, load deflection characteristics and porosity were studied. It was inferred from the results that high performance concrete with 1.5% volume of fiber with water-binder ratio of 0.25 performed well. Load carrying capacity of high performance fiber reinforced concrete was found to be higher than the control concrete.

After Northridge earthquake several connection configurations have been proposed by researchers to improve the ductility of the rigid connections. One of them is welded flange plate (WFP) connections. These connections have been used in Iran for years but withdifferent details from what is presented by the Federal Emergency Management Agency (FEMA). In present study a parametric study on the strength and ductility of WFP connections in the case of utilizing deep beams has been carried out using finite element method. These parameters are; beam material property, flange plate thickness, flange plate length, the transverse welding of the top flange plates, the end form of the top flange plate, the equality or inequality of the top and bottom flange plate length, form of the rib plates and the common methods to transfer the shear force from the beam to the column. Finally, the effects of doubler plates to increase the strength and ductility of the WFP connections were investigated.

Natural clay soils due to anisotropy have a different behavior from disturbed and remolded specimens. The Modified Cam Clay (MCC) model, as a fundamental critical state model, cannot capture this behavior with enough accuracy. However, anisotropic models that known as rotational hardening models can efficiently simulate the anisotropic behavior. Specifically, SANICLAY model, which has been recently developed, has a high accuracy in modeling of the anisotropy and thus is used in the present study. Here, a semi-explicit constitutive integration scheme is proposed and validated for the SANICLAY model. It is then implemented in FLAC software through a UDM subroutine. Several triaxial simmulations are carried out and the results are compared with the MCC model results. Advantages of the proposed integration method in terms of stability, accuracy and speed are discussed.

This paper presents a study on the strength and ductility performance of steel fibre reinforced concrete (SFRC) beams with externally bonded glass fibre reinforced polymer (GFRP) laminate. The beams were incorporated with 1.0% volume fraction of steel fibres randomly distributed throughout the section. The parameters of this investigation included first crack load, yield and ultimate load, crack width, and ductility. Two groups of beams were cast and tested in the laboratory. Each group consist of two beams: group A having reinforced concrete (RC) beams with and without externally bonded GFRP laminate and in group B, SFRC beams with and without externally bonded GFRP laminate. The experimental results show that GFRP laminated SFRC beams improve strength and ductility performances appreciably.

Composite structures play a major role in the design and construction of multi-storeyed buildings. It has positive prospects like, high strength, corrosion resistance, combined utilisation of both the material properties, etc. In present work, an experimental study was made on the behaviour of concrete encased I-shape steel short columns under axial compression was considered. The mineral admixture namely metakaolin (MK) was added 15% as replacement of cement for developing self compacting concrete (SCC) specimens. The experimental programme was developed with the two composite specimens namely, one composite short column specimen with conventional vibrated reinforced cement concrete (CVC) and the another composite short column specimen with reinforced self compacting concrete (SCC) with M60 grade as per ACI code. The significance of the investigation was to examine maximum compressive load of composite short column under static loading conditions by varying the high strength concrete type. The comparison of structural behaviour of CVC and SCC composite short columns was obtained. Finally the load displacement curve and stress strain curve was plotted to study and compare the behaviour of both types of short composite columns.

In the method of identification of structural damage utilized in the structural healthmonitoring problems, a search is carried out to find the location and damage severity ofstructural members by checking every possible value of these damage severities. Recently,researchers have been solved this problem using optimization algorithms. This paperexamines the application of recently developed optimization algorithms, so-called Colliding Bodies Optimization (CBO) and Enhanced Colliding Bodies Optimization (ECBO), in conjunction with structural modal information for damage detection of steel trusses. The performance of the presented technique has been is verified through three numerical examples. Comparative studies illustrate the superiority the ECBO algorithm compared to the standard CBO algorithm.

This study investigates the behaviour of tall staggered wall buildings in which the external load bearing walls of the structure is achieved by staggered wall arrangement along the height of the structure. Complete Perspex tall staggered wall structure model is fabricated and the complex model is subjected to static and shaking table vibration tests. Simplifications in the analytical approach are implemented and the final idealized model of the staggered wall structures to predict the behaviour of staggered wall building is analysed. The simplified approach predicted good agreement of deflections with static tests and the shaking table natural frequency results have shown some discrepancies within the normal bond of the experiments.

Instead of the usual neglecting, this study takes advantage of the second-order axial strain terms in the elastic constitutive equation of three-dimensional truss. This leads to higher-order terms on the resulting unbalanced force and on its corresponding tangent stiffness. The finite element procedure and updated Lagrangian descriptions are utilized with the new stiffness matrix. Furthermore, governing equilibrium equations are solved by using cylindrical arc-length approach. The validity of the proposed algorithm is checked by numerical examples. The outcomes indicate that the authors'' formulation possesses the ability to trace the equilibrium path completely. Moreover, the obtained answers are identical with the exact results of other researchers.

The second most consumed product in the world is Cement. It contributes nearly 7% of the global carbon dioxide emission. Geopolymer concrete (GPC) is becoming a special type of more eco-friendly concrete alternative to Ordinary Portland Cement (OPC) concrete. This project mainly aims at the study of effect of class F fly ash (FA) and ground granulated blast furnace slag (GGBS) on the mechanical properties of geopolymer concrete (GPC) at different replacement levels (FA50-GGBS50, FA25-GGBS75, FA0-GGBS100) using Sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) solutions as alkaline activator. Specimens were cast and cured for different curing periods at ambient room temperature to determine the GPC mechanical properties viz. compressive, splitting tensile and flexural strength. Test results reveal that increase in GGBS replacement enhanced the mechanical properties of GPC at all ages at ambient room temperature.

Cold formed steel channel sections bolted at the end supports are widely used almost in all construction fields to form integral part of structural members. In order to promote the effective utilization of cold formed steel structures, it is important to have a detailed investigation on the behaviour of cold formed steel members. This paper investigates bolted channel members subjected to tension which influences the shear lag effect. The thickness of the cold formed steel sheet was 2mm. Twelve plain channel members with different dimensions are bolted to gusset plate using bolts of 10mm diameter, are tested in an Universal Testing Machine. All the specimens were tested till failure. The ultimate load carried by the specimens were compared with the theoretical load capacity by various codes such as AISI 2007, AS/NZS 4600, BS 5950-part 5 1998 and also with the load carrying capacity predicted by ANSYS.