Introduction:This study presents the experimental and analytical investigation of the behavior of high strength hybrid reinforced concrete deep beams under monotonic and repeated two-point load. The idea of hybrid in this work is different. Two types of concrete were used in beam but not in cross-section. The first type was the Fibrous High Strength Concrete (FHSC) at shear spans for enhancing shear capacity against cracking due to diagonal strut failure (by adding Steel Fiber (SF) in that regions), while the second type was the Conventional High Strength Concrete (CHSC) at the mid-portion between the two strengthened shear spans.Methods:The experimental work included the casting and testing of ten deep beams. Five among the beams were tested under monotonic loading (control beams) and other beams were tested under repeated loading at the level of 75% of ultimate load of control beams. The effect of some selected parameters as the type of load, the hybrid and non-hybrid beams, the compressive strength of concrete (fʹc) (normal and high) and the amount of web reinforcement (ρw) were studied in terms of crack patterns, ultimate load and load versus midspan deflection.Results and Conclusion:From the experimental test results, when beam cast with fibrous with SF of 1% concrete along entire length, the ultimate load of 10.96% increased as compared with hybrid beam. And it was observed to increase as much as 32.78% as compared with beam cast from conventional high strength concrete under monotonic loading. Under repeated loading of 75% control ultimate load, the ultimate load for beam cast with fibrous concrete along entire length increased as much as 15.32% as compared with hybrid beam. And it was seen to increase 36.17% as compared with the beam cast from conventional high strength concrete. The percentage increase in ultimate load of hybrid (SF ratio 1%) deep beam cast with high strength concrete became 97.3% as compared with the identical beam cast with normal strength concrete under monotonic loading and (98.21%) under repeated loading (load 75% control beam load). The percentage increase as ultimate load for hybrid beam cast with SF ratio 1% was 9.62% as compared with hybrid beam with SF ratio 0%. As the web reinforcement increased from 0 to 0.004 and from 0 to 0.006, the percentage increased in the ultimate load as 28.07% and 57.89%, under monotonic loading as 26.14% and 59.09%, under repeated loading.Then, Strut and Tie model (STM) procedures were used to analyze the experimentally tested hybrid deep beams under monotonic loading of the present investigation. Comparison of experimental results was made with corresponding predicted values using the STM procedure presented of ACI 318R-14 Code and with other procedures

Objective: The purpose of this paper is to present an overview of the specifications of three guidelines for the seismic design of structures with passive dampers, to compare their similarities, as well as to discuss topics in which each guideline would be desirable to extend. The guidelines compared here are: a) Minimum Design Load for Buildings and Other Structures (ASCE/SEI 7-16), b) European Standard Anti-seismic Devices (EN 15129), and c) Technical Regulations for Seismic Design, corresponding to Mexico City Building Code (NTCS-17). Methods: The document summarizes and discusses the most significant differences and similarities among the three guidelines for the design of structures with energy dissipation devices. The analysis and discussion are focused on the following sections: 1) Type of Dissipation Devices, 2) General Design Requirements, 3) Procedure Selection, 4) Seismic Design Action, 5) Inspection and 6) Testing of Dissipaters. Conclusion: The paper identifies the gaps in each guideline and gives recommendations about its possible extension. The paper concludes that ASCE/SEI 7-16 presents the procedure selection section with more detail; EN 15129 describes with more detail the Testing section, and NTCS-17, the Inspection section. The paper can be useful for engineers and guideline writers from the USA, Europe, Mexico and other countries that are in process of developing their guidelines for structures with supplementary damping.

Introduction: The present work presents experimental and analytical investigation of the effect of steel fiber ratio of behavior of high strength hybrid reinforced concrete deep beams under monotonic and repeated two point load. Methods: The experimental work included casting and testing of six deep beams, three of which were tested under monotonic loading (control beams) and other beams were tested under repeated loading at level of 75% of ultimate load of control beams. The effect of different SF ratios (0%,1% and 2%) with constant amount of web reinforcement (pw) were studied in terms of crack patterns, ultimate load and load versus mid span deflection. Results and Conclusion: From the experimental test results, it was observed the percentage increase ultimate load for hybrid beam cast with SF ratio 1% is 9.62% as compared with hybrid beam with SF ratio 0%. Also, the ultimate load for hybrid beam cast with SF ratio 2% is 28.85% as compared with hybrid beam with SF ratio 0% and 17.54% as compared with hybrid beam with SF ratio 1% under monotonic loading. Strut and Tie Model (STM) procedures were used to analyze the experimentally tested hybrid deep beams under monotonic loading of the present investigation.

Introduction:Reliability analysis is a good tool to deal with the uncertainty and has been widely used in the engineering system. The first order reliability method (FORM) is generally used to calculate the reliability index but FORM is time-consuming and requires derivative computing.Methods:Artificial Bee Colony (ABC) algorithm is a very simple, robust and population-based stochastic optimization algorithm. In this study, an ABC-based reliability analysis was proposed to calculate the reliability index of engineering system through combining Artificial Bee Colony (ABC) algorithm with FORM. FORM was adopted to calculate the reliability index and design point. ABC is used to solve the constrained optimization about FORM. The procedure of ABC-based reliability analysis was presented in detail.Results and Conclusion:The proposed method was verified by two classic examples and then applied to geotechnical engineering. The results show that the ABC algorithm can effectively solve the global optimization problem in FORM. Results demonstrate that ABC-based reliability analysis is a good approach to obtain the reliability index and design point with a good accuracy so that it can be applied to analyze the reliability of a complex engineering system.

Introduction: The sandwich joints casted core area with weaker strength concrete of beam, has more advantages than the traditional joints casted core area with higher strength concrete of column, such as the simple construction and quality assurance, while China design codes are too simple about the sandwich joints and have no clear calculation methods. Methods: Due to the scarcity of rational models for predicting the strength of RC beam-column sandwich joints, a modified simplified softened strut-and-tie model suggests a more rational calculation method for the effective compressive strength and the height of the joint concrete based on the simplified softened strut-and-tie. The shear strength of existing tested 15 sandwich interior joints is calculated by using the modified simplified softened strut-and-tie model. Furthermore, the theory results are compared with those of the code method and those of the simplified softened strut-and-tie model. Results and Conclusion: The results indicate that the code method is more conservative, and the modified simplified softened strut-and-tie can more precisely predict the joint shear strength than that of the softened strut-and-tie model and more secure than that of the code method. Thus, the modified simplified softened strut-and-tie model can reasonable reveal the failure mechanism of RC beam-column sandwich interior joints.

Background: In this study, piezoelectric sensors were embedded into concrete structures to monitor dynamic response. The embedded piezoelectric sensors had sensitive frequency and linear response. Objective: In the experiment, two loading conditions were applied to the concrete cantilever beam and concrete frame. The dynamic properties could be monitored using the embedded sensors and the damage could also be identified.

Introduction: Blind analysis contests for predicting the results of several collapse tests on RC frame structure, were carried out by the Collapse Prevention Committee of Architectural Society of China in 2011. This paper presents the adopted numerical models for the collapse simulations of four RC column tests and one RC frame test. Methods: The columns and beams in the RC frame were modeled by beam elements using the fiber model of THUFIBER program. The confined effect of the stirrups in the square RC column was taken into account by using the backbone curve of confined concrete. The methods to determine the key parameters of the adopted model were introduced. Results and Conclusion: The prediction results were compared with the test results, and the adopted models exhibited good predictions for the general behavior of both the RC columns and frame. The model was proposed for investigating the collapse mechanism of RC frames.

Introduction: This paper presents results from a set of numerical studies on the cracked reinforced concrete column at high temperature. Methods: The macroscopic finite element model used in the accounts analysis for high temperature properties of constitutive materials. The validity of the model is established by comparing the predictions from numerical analysis with the data measured in the fire test. Result and Conclusion: Data from the test indicated that the temperature of rebar in column with cracks is 57% ~ 130% higher than that without cracks under the same condition, and different types of crack had significant influence on the bearing capacity of column. These results from parametric studies were utilized to propose ultimate bearing capacity of cracked reinforced concrete column.

Introduction: The design of direct embedment pole foundations involves calculating the ultimate moment capacity and deflections/rotations of pole foundations at groundline. Methods: A theoretical model based on rigid piles is used as a basis for developing equations for the ultimate moment capacity of direct embedment pole foundation installed in granular soils. Results and Conclusion: The steps involved in the development are presented in this paper. Prototype test data are used to compare the predictions of the model and to validate the proposed method.