Journal of Civil Engineering Beyond Limits (CEBEL)

Tirimisiyu Buari Festus Olutoge Gbenga Ayininuola Agbanah-Owa O.A.

This research investigated the comparative structural response of a straight and curved continuous bridge deck subjected to realistic working loads. The study involved examining the variance in analysis results obtained whilst utilising the grillage and finite element methods for an idealized bridge deck. The combined impact of continuity at the intermediate support and the curvature on the overall structure was examined. The idealized case study is a 45m two-span continuous bridge deck with a 22.5m straight span and an equivalent 22.5m curved span with a centerline radius of approximately 14.32m. The bridge deck was designed for design dead load and 45 units of HB load, these loads were computed based on recommendations given in BS 5400-2:2006 and BD 37/01 Volume 1 ,2001[1,2]. For the Grillage Analysis Sap2000 version 22 software was utilized while CSI Bridge version 21 was used to simulate the Finite Element model. The findings from the study revealed that the results obtained from the grillage analysis method were more conservative in regards to midspan sagging moments and support shear force. However, the finite element analysis result was more conservative for support hogging moments, deflection and torsional moments. It was concluded that finite element analysis result values differed from the grillage analysis, but the values were close enough with the disparity not calling for serious concerns.

https://doi.org/10.36937/cebel.2021.003.001

Ahmed Al-Khalili Ahmed Ali Abbas Al-Taie

Engineering structures found in, or on, some clay soil types may be subject to different damages due to the problematic nature and unfavorited properties of these soils. The unfavorited properties of these soils include shrink and swell changes, high settlement, and low bearing capacity. These soils have high sensitivity to moisture change. The way to reduce or overcome the unfavorited properties of problematic soils is the treatment or enhancement of these soils using different mechanical or chemical methods. In the present paper, silica fume selected as a soil stabilizer material, the effect of different contents of this material on the geotechnical properties of expansive clay soil has been experimentally investigated. Tests included soil-specific gravity, soil plasticity, soil compaction, and soil compressibility. It was noted that silica fume, with different contents, decreased the specific gravity, and compaction density, while the compaction water content and Atterberg limits increased. The consolidation parameters of the expansive clay soil were affected by adding the silica fume. The silica fume reduced the consolidation parameters values of the clay soil. At low content silica fume, less than 10%, a very slight reduction can be seen especially for the rebound index value. The final findings of this paper appeared that the high settlement of clay soil can be reduced with the presence of silica fume.

https://doi.org/10.36937/cebel.2021.003.002

Ahmed Mancy Mosa Lubna Abdulrahman Salem Qais Sahib Banyhussan

Highway engineers encounter numerous problems during rigid pavement concreting. Thus, deciding on appropriate controlling measures is a crucial task. These problems affect the quality of pavements and increase initial cost. Experts can control them, but novices cannot. Therefore, this study describes the development of a novel knowledge-based system to control concreting problems of rigid pavements. The knowledge that includes problems encountered in the domain, their causes, preventive actions, solutions, and their effects was acquired from the experts by different methods and was presented in a classified format. The calcified knowledge was transferred into rules and coded in software by using Visual Basic. The system was tested by different users involved in highway engineering, including experts and novice engineers. The mean values of the overall system evaluation by the four types of users based on the 5-point Likert scale were 4 and 4.5 respectively. The developed system can be used to help highway engineers overcome the problems during concreting of rigid highway pavements, identify their causes, preventive actions, and effects on the construction process. It can also be used to help the experts formulate decisions quickly. The system facilitates decision making of domain experts by reducing unnecessary inputs, performing quick calculations, and providing classified recommendations. In addition, it can be used as an instructional tool for pavement engineers or highway engineering students, to interchange the expertise among the experts, and to transfer expertise to the next generation of engineers.

https://doi.org/10.36937/cebel.2021.003.003

Md Roknuzzaman Md Belal Hossain Afroja Sultana Abdullah Al Shourov

Performance of plain concrete with partial replacement of coarse aggregate by rubber chips derived from the waste tire is taken into consideration and an attempt is made to investigate the influence of rubber size on strength, workability, and durability. Four different size ranges of tire chips such as 4.75-9.5 mm, 9.5-12.5 mm, 12.5-19 mm, and 19-25 mm are used to replace stone aggregates of corresponding sizes. A 7.5% replacement of coarse aggregate is made each time. Concrete of three different grades such as C20/25, C25/30, and C30/35 are considered. For every concrete grade, compressive strength is reduced with the addition of tire chips, but less strength loss is observed for the smaller-sized tire chips. Therefore, the best size is found to be 4.75-9.5 mm yielding a compressive strength 8.33%-18.48% (for different concrete grades) lower than that of corresponding control specimens. The workability of each mix based on slump value is found to increase with larger tire chip size. The durability inspection by acid curing reveals that 4.75-9.5 mm rubber performs best with a minimal strength reduction of 8.99%-16.38% as compared to the same specimen subjected to conventional water curing. Strength degradation is found to be more severe in the cases of the control specimen with lower strength.

https://doi.org/10.36937/cebel.2021.003.004

Mohammad Taghi Hamzaban Ismail Sedat Büyüksağiş Ali Touranchehzadeh Milad Manafi

Different major factors control the strength of solid rocks. Moisture content is one of the most important factors, which can change the physical and mechanical behavior of intact rock as well as rock mass. Several early studies have shown that rock is weaker if tested wet rather than dry. In this paper, the density, P-wave velocity, uniaxial compressive strength, Brazilian tensile strength, and modulus of elasticity of seven different intact rock samples were measured under both dry and saturated conditions. The porosity of the samples was reported as well. Based on the obtained results, some correlations were proposed for estimating the saturated physical and mechanical properties from dry ones. The proposed correlations include different rock types and are more general than the previously reported ones. Comparing the obtained results showed that the mechanical and physical properties of weaker samples are more sensitive to the saturation process. Moreover, among the different mechanical parameters, Brazilian tensile strength exhibited more sensitivity to saturation. Comparing the results with the calculated porosities revealed that porosity is one of the key factors in the effect of saturation on physical and mechanical parameters. It seems that in the more porous rock samples, greater changes in the different measured parameters occur after saturation.

https://doi.org/10.36937/cebel.2021.003.005