Reliability analysis of slender columns using the general method with linear creep theory

To analyze the reliability of slender columns subjected to axial force and uniaxial bending moment, with a slenderness index between 100 and 140, 216 columns were modeled. The square cross-section was adopted, with three different configurations for longitudinal reinforcement. In the calculation, the general method with the linear creep theory was applied. Several factors were varied: slenderness index, reinforcement ratio, steel bars arrangement, compressive strength of concrete, and first-order relative eccentricity. For analysis purposes, the Monte Carlo method was adopted, followed by the First Order Reliability Method (FORM). Considering the results obtained, it was observed that the reliability index is usually higher for lower reinforcement ratios and varies according to the configuration of the cross-section.

Effect of the connecting beam stiffness on the bracing limit for reinforced concrete slender columns in single and multi-story frames

The main purpose of this paper is to study analytically the behavior of slender reinforced concrete columns existing in sway and non-sway structures. The studied variables were the stiffness of the beam connected to the slender columns, the stiffness of the bracing columns, and the number of bays and stories in the structure model. The stability of slender columns was studied and the required limits for the lateral bracing were determined using a finite element program to perform buckling analysis, linear analysis, and geometric nonlinear analysis for the different frame structural models. All the results obtained in this study were compared to the available methods included in the different building codes and the methods suggested by other researchers. The results indicated that the minimum value of the bracing limit, required to restrain the slender column against the side-sway, depends on the stiffness of the connecting beams, number of stories, and number of bays. The required bracing limit decreases with increasing the beam stiffness and with increasing the number of bays. However, the required bracing limit increases with the increase of the number of stories in the structure.

Assessment of Concrete Filled Steel Tubular Members: An Experimental Review

In this world with rapid development, durable and fast construction techniques lead to the invention of composite materials that are robust and advantageous over conventional materials. Recently invented Concrete-filled steel tubular members are the composite members used in civil engineering works to replace conventional steel and concrete members. This paper deals with an overview of the experimental performance of various types of composite members such as columns, short columns, stub columns, beam-columns, and slender columns deals with various loads such as axial compression, flexural load, cyclic bending, long-term sustained load, torsional load, and impact load. Effects due to the variation in the parameters like steel and concrete strength, diameter to thickness ratio, axial load level, shapes of tubes of these composite members on load-carrying capacity, flexural stiffness, ductility, torsional capacity, and cyclic performance of these members are discussed in this paper. The future scope is mentioned for study related to these composite members in the paper.

Probabilistic and Semi-Probabilistic Analysis of Slender Columns Frequently Used in Structural Engineering

The stability of slender columns is a topic that has been dealt with in research and practice for many years. The importance of this topic also increases with the possibility of using non-linear modeling approaches to determine the stability and with the increasingly complex safety formats. In order to show the complexity and the variability associated with the non-linear models, two previous contributions discussed and compared (a) the results of the Round Robin Non-Linear Modeling, and (b) the existing international associated standard specifications and safety concepts with respect to experimental results. The aim herein is to determine the reliability level (safety index) on the basis of these investigations and findings and to examine the existing safety formats of classical and extended probabilistic analyses and to derive any necessary adjustments. In addition, the method of the safety format Estimation of Coefficient of Variance of resistance (ECOV) is used for the determination of the global safety resistance factors based on the non-linear analyses’ findings of the Round Robin modeling partners.