Engineering and Technology Journal

High-performance fiber-reinforced concrete is a new class of concrete that has been developed in recent decades. It exhibits enhanced properties such as high compressive strength and improved tensile strength. Three types of concrete with different compressive strengths, namely, normal-strength concrete, high-strength concrete, and high-performance concrete, were used in this study. The experimental program included casting and testing sixteen reinforced concrete deep beams without stirrups to study the shear strength and behavior of these beams under two-point loading. The variables considered were the compressive strength of concrete (f′c ) (40–120 MPa), shear span-to-depth ratio (1, 1.5, 2, 2.5, and 3), and the ratio of the amount of flexural steel bar ratio (1.35%, 2.40%, 3.76%, and 6.108%). Experimental results showed that increasing concrete compressive strength and flexural steel bar ratio increased ultimate shear capacity. By contrast, increasing shear span-to-depth ratio and span-to-depth ratio reduced ultimate shear capacity. Based on the test results of this investigation (16 beams) and those of available literature (233 deep beams), an equation that considered the parameters affecting shear stress (f′c, l/d, a/d, andw) was proposed using SPSS software. The proposed equation was compared with predictions made by the American Concrete Institute (ACI) and the works of other researchers, including that of Zsutty and Aziz. The ACI predictions were conservative and the proposed equation had a lower coefficient of variation.

The mathematical procedure in this study covers the calculation of sectorial
properties of the equivalent cross-sectional storey for high-rise building frames. The
formulation is efficiently used to obtain the free vibration analysis of high-rise
buildings which are constructed from several columns, beams, shear walls and
bracing etc. the analysis is based on transformation the complex system to a simple
tall column to represent a cantilevered tall building structure. This is partitioned to
nodes one of which indicates a storey with equivalent cross-sectional properties for
all storeys' elements after calculation of these properties with respect to the shear
center of high-rise building. A thin walled bar finite element with seven degrees of
freedom at each node is assumed. A new formulation of the stiffness and consistent
mass matrices of the thin- walled element is presented in this study. The effect of
cross sectional warping and its properties on the flexural, torsional and axial
properties was investigated, using discrete element approach in idealizing the
structure in high rise building. For the purpose of the present study, it is assumed
that the cross-sectional types under condition are only of thin-walled sections.
Algorithm method was developed which covers the calculation of sectorial
properties of the cross section for floor plan in high-rise building, to study the share
of columns for lateral shear force resistance, and investigate the behavior of different
types of high-rise building with inclusion of warping restraint. The effect of natural
frequency with height of tall buildings, and the mode shape for different crosssectional
plans of high-rise building was studied. To check the efficiency and
accuracy, the mathematical procedure is demonstrated for static and dynamic
examples by comparing the results with those obtained by using software ANSYS
program. A difference of 15% is shown. An eigen value problem is analyzed and
numerical examples are discussed.

This work examines the work of 13 high-strength concrete (HSC) beamcolumn
joints (BCJ)-with and without steel fibers. Several shear design methods
(with modification for fiber content, where applicable) were found to be
conservative within a range of the following variables: 1) concrete compressive
strength, 2) type and volume fraction of steel fibers, 3) content of hoops in the
joint, and 4) column axial load. The coefficient of variation (COV) of the ratio
of test strength to design strength (VTEST / VrDES) was found to be appreciably low
for two of the five existing safe design methods. A conservative design method,
which lowers the COV even further to a value of 7.8 percent, is proposed for HSC
joints, with and without steel fiber reinforcement

This work aim to study the effect of transverse reinforcement , area of splice
bar, concrete cover thickness , rib area and the increasing in concrete strength (highstrength
concrete) on bond strength between concrete and reinforcing spliced bars .
Therefore, a new simple equation is derived for beams with spliced bars and
confined by transverse reinforcement to calculate bond strength and reflects the
effects of these factors .Where many of existing codes and provisions used to
calculate the spliced strength do not include or reflect the influencing of these factors
in bond strength estimation . Based on experimental results from previous works ,
(116) confined beams with spliced bars are investigated in this study , where
concrete compressive strength ( c f ¢
) ranging from 25 MPa to 113.793 MPa ,amount
of transverse reinforcement vary in a wide range and , conventional and high
relative rib area of deformed bars are present in these beams . The proposed method
exceed the limitation of ( f MPa c ¢ £ 69 ) that given by ACI code .Where the
proposed method is examined and applicable for concrete compressive strength up
to 113 MPa . Also, in this work the second root of c f ¢
is examined , as concrete
strength increased with high-strength concrete , to reach a suitable value for both
normal and high- strength concrete and to be more appropriate with the heavy
present of transverse reinforcement . Power of (0.35) is adopted and used in this
work instead of the second root of c f ¢