The Experts below are selected from a list of 12003 Experts worldwide ranked by ideXlab platform
M Reza Salami - One of the best experts on this subject based on the ideXlab platform.
-
COARSE-AGGREGATE EFFECT ON MECHANICAL PROPERTIES OF Plain Concrete
Transportation Research Record, 1993Co-Authors: M Reza Salami, Gary S. Spring, Shilong ZhaoAbstract:The influence of three coarse-aggregate types on the relationships between compressive and tensile (split tensile and modulus of rupture) strengths of a Plain Concrete was investigated. It was found that, in some cases, aggregate type has significant effects on these strength relationships. The mineralogical differences in the aggregate types are considered to be responsible for this behavior. The commonly accepted 0.5 power relationship between compressive strength and tensile strength was found to be applicable neither for all aggregate types nor at different ages. From the available experimental data for modulus of rupture and splitting tensile strengths of Concrete, alternative relationships between the tensile and compressive strengths were calibrated and are presented. Finally, a previous study of the effect of three coarse aggregates on the coefficient of linear thermal expansion and water-cement ratio was discussed and enhanced using graphic representations of the relationships. The correlation between the experimental results and analytical predictions provides a simple approach for developing tensile strength models for Plain Concrete using three types of aggregate. Tables of results and figures supporting these observations and conclusions are included.
-
CONSTITUTIVE RELATIONS AND FAILURE MODEL FOR Plain Concrete AND STEEL-FIBER-REINFORCED Concrete (ABRIDGMENT)
Transportation Research Record, 1992Co-Authors: M Reza SalamiAbstract:A constitutive model based on the theory of plasticity is proposed and utilized to characterize the stress-deformation behavior of Plain Concrete and steel-fiber-reinforced Concrete. It allows for factors such as stress hardenings, volume changes, stress paths, cohesive and tensile strengths, and variation of yield behavior with mean pressure. It is applied to characterize behavior of Plain Concrete and steel-fiber-reinforced Concrete. The constants for the model are determined from a series of available laboratory tests conducted under different initial confinements and stress paths obtained by using multiaxial and cylindrical triaxial testing devices. The model is verified with respect to observed laboratory responses. Overall, the proposed model is found suitable to characterize the behavior of Plain Concrete and steel-fiber-reinforced Concrete.
Ning Xiao - One of the best experts on this subject based on the ideXlab platform.
-
experimental study and failure criterion analysis of Plain Concrete under combined compression shear stress
Construction and Building Materials, 2018Co-Authors: Qiao Huang, Xinghua Xie, Ning XiaoAbstract:Abstract To study the mechanical properties of Plain Concrete (with a standard compressive strength of 30 MPa) under combined compression-shear stress, the Concrete was tested using material compression-shear hydraulic servo machine under various axial compression conditions. In the experimental study, the shear failure modes and shear load-displacement curves of Concrete are obtained. The peak shear strength and residual strength of Concrete are then extracted from the load-displacement curves. A total of three development stages of shear load-displacement curves are identified and mechanical characteristics at each stage are analyzed. The results show that the shear failure behavior of Concrete under different axial compression is quite different, and as the increase of axial compression ratio, the traces of friction on shear plane get more evident and the Concrete failure slag also increases. Based on the experiment data and regression analysis, it is observed that both the peak shear strength and residual strength of Concrete increase linearly as the increase of axial compression ratio. From the residual strength analysis, the shear failure plane of Plain Concrete has a relatively stable friction coefficient of 1.46. According to octahedral stress space analysis and unified strength theory, the failure criterion curves of Concrete under compression-shear stress are obtained and the results fit the test data well. The proposed two types of failure criterion theories can effectively model the strength law of Plain Concrete under combined compression-shear stress.
Mohammad S. Marefat - One of the best experts on this subject based on the ideXlab platform.
-
intensity measures for the seismic response assessment of Plain Concrete arch bridges
Bulletin of Earthquake Engineering, 2018Co-Authors: Vahid Jahangiri, Mahdi Yazdani, Mohammad S. MarefatAbstract:Intensity measures (IMs) are used as a link between seismic hazard and seismic demand analysis and therefore have a key role in performance-based earthquake engineering. To the best of our knowledge, no study has been carried out on the determination of suitable IMs to evaluate the seismic demand of Plain Concrete arch bridges. In the present study, the efficiency, sufficiency, scaling robustness and practicality of 34 potential IMs for evaluating the seismic response of two old railway Plain Concrete arch bridges in km-23 and km-24 of Tehran–Qom railway are investigated. The considered bridges are simulated using finite-element method and subjected to incremental dynamic analysis (IDA) using 22 far-field earthquake ground motion records. Complete response of the models is obtained through IDA method in terms of engineering demand parameter measured by the maximum displacement of the bridges. The optimal IMs among the considered intensity measures for evaluating seismic demand of the investigated Plain Concrete arch bridges are recognized using the concepts of efficiency, sufficiency, scaling robustness and practicality. Using the results of the regression analysis, it is concluded that root mean square acceleration is the optimal IM based on efficiency, sufficiency, scaling robustness and practicality for seismic response evaluation of Plain Concrete arch bridges under far-field ground motions.
H.h. Chen - One of the best experts on this subject based on the ideXlab platform.
-
Tension softening curves of Plain Concrete
Construction and Building Materials, 2013Co-Authors: H.h. ChenAbstract:The tension softening curves (TSCs) of Plain Concrete with compressive strengths varying between 40 and 90 MPa were estimated by performing three-point bending tests on pre-notched beams. Crack evolution and full-field deformation in the beams were measured using the electronic speckle pattern interferometry technique. The crack characteristics, including the crack opening displacement profiles, the width of the fracture process zone and the length of the crack, were evaluated. By using a newly developed incremental displacement collocation method, the TSCs of Plain Concrete were determined. To facilitate the use of TSCs by commercial finite element packages, the estimated TSCs were simplified to bilinear and exponential curves, and the related parameters were determined.
Norbert Will - One of the best experts on this subject based on the ideXlab platform.
-
Load-bearing capacity of Plain Concrete walls
Magazine of Concrete Research, 2009Co-Authors: Josef Hegger, T. Dressen, Norbert WillAbstract:Walls in housing are usually made of masonry or reinforced Concrete. These wall constructions are both labour- and material-intensive and therefore more expensive than walls made of Plain Concrete. The high wall-thickness required by the design rules of BS 8110-1 and Eurocode 2 is the most important restraint for the use of Plain Concrete walls. The different design approaches are discussed and a new design method is exPlained in this paper. The proposed model allows for a simple, standardised and economic design of Plain Concrete walls with a thickness less than that of masonry walls. A further increase in load-bearing capacity can be achieved by taking into account the Concrete tensile strength. A comparison with a test database verifies that all relevant aspects of the load-bearing capacity, for example slenderness, eccentricity and Concrete strength, are represented appropriately by the developed design method. Moreover, the safety level of EN 1990 can be achieved.
-
Static system of Plain Concrete basement walls under earth pressure
Magazine of Concrete Research, 2009Co-Authors: Josef Hegger, T. Dressen, J. Niewels, Norbert WillAbstract:The equivalent static system of basement walls under earth pressure is very important to determine the required wall thickness. Reversing moments due to eccentric loading at the top and bottom of the wall lead to lower design moments in the middle third of the wall. Eurocode 6 proposes an eccentricity of h/3 for the structural design of basement masonry walls. This limitation results from safety against lateral buckling. In contrast to the design of Plain Concrete basement walls, no value for the eccentricity is provided in Eurocode 2. However, finite-element simulations show that Plain Concrete has a sufficient ductility to enable reversing moments at the top and bottom of the wall due to eccentric loading. This is independent of the distortion of the basement floor and foundation. By estimating an equivalent static system with reversing moments a high reduction of the required wall thickness can be achieved. Furthermore, Plain Concrete walls are less labour- and material-intensive and therefore more eco...
