Lecture 12 equivalent frame method

The document discusses ductility and ductile detailing in reinforced concrete structures. It states that structures should be designed to have lateral strength, deformability, and ductility to resist earthquakes with limited damage and no collapse. Ductility allows structures to develop their full strength through internal force redistribution. Detailing of reinforcement is important to avoid brittle failure and induce ductile behavior by allowing steel to yield in a controlled manner. Shear walls are also discussed as vertical reinforced concrete elements that help structures resist earthquake loads in a ductile manner.

Advancement of softwares is main cause behind comparatively quick and simple design while avoiding complexity and time consuming manual procedure. However mistake or mislead could be happened during designing the structures because of not knowing the proper procedure depending on the situation. Design book based on manual or hand design is sometimes time consuming and could not be good aids with softwares as several steps are shorten during finite element modeling. This book may work as a general learning hand book which bridges the software and the manual design properly. The writers of this book used linear static analysis under BNBC and ACI code to generate a six story residential building which could withstand wind load of 210 kmph and seismic event of that region. The building is assumed to be designed in Dhaka, Bangladesh under RAJUK rules to get legality of that concern organization. For easy and explained understanding the book chapters are oriented in 2 parts. Part A is concern about modeling and analysis which completed in only one chapter. Part B is organized with 8 chapters. From chapter 1 to 7 the writers designed the model building and explained with references how to consider during design so that creativity of readers could not be threated. Chapter 8 is dedicated for estimation. As a whole the book will help the readers to experience a building construction related all facts and how to progress in design. Although the volume I is limited to linear static analysis, upcoming volume will eventually consider dynamic facts to perform dynamic analysis. Implemented equations are organized in the appendix section for easy memorizing. BNBC and other codes are improving and expending day by day, by covering new and improved information as civil engineering is a vast field to continue the research. Before designing something or taking decision judge the contemporary codes and choose data, equations, factors and coefficient from the updated one. Book for Beginners series is basic learning book of YDAS outlines. Here only rectangular grid system modeling and a particular model is shown. Round shape grid is avoided to keep the study simple. No advanced analysis is described and it is kept simple for beginners. Only two way slab is elaborated with direct design method, avoiding other procedures. In case of beam, only flexural and shear designs are made. T- Beam, L- Beam or other shapes are not shown as rectangular beam was enough for this study. Bi-axial column and foundation design is not shown. During column and foundation design only pure axial load is considered. Use of interaction diagram is not shown in manual design. Load centered isolated and combined footing designs are shown, avoiding eccentric loading conditions. Pile and pile cap design, Mat foundation design, strap footing design and sand pile concept are not included in this

- The document discusses the design of a combined footing to support two columns carrying loads of 700 kN and 1000 kN respectively. - A trapezoidal combined footing of size 7.2m x 2m is designed to support the loads and transmit them uniformly to the soil. - Longitudinal and transverse reinforcement is designed for the footing and a central beam is included to join the two columns. Detailed design calculations and drawings of the footing and beam are presented.

Shear walls are vertical reinforced concrete walls that resist lateral forces like wind and earthquakes. They provide strength and stiffness to control lateral building movement. Shear walls are classified into different types including simple rectangular, coupled, rigid frame, framed with infill, column supported, and core type walls. Design of shear walls involves reviewing the building layout, determining loads, estimating earthquake forces, analyzing the structural system, and designing for flexural and shear strengths with proper reinforcement detailing. The behavior of shear walls under seismic loading depends on their height to width ratio, with squat walls experiencing more shear deformation and slender walls undergoing primarily bending deformation.

this slide will clear all the topics and problem related to singly reinforced beam by limit state method, things are explained with diagrams , easy to understand .

Retrofitting: Upgrading of certain building systems (existing structures) to make them more resistant to seismic activity.

The document discusses the moment distribution method for analyzing statically indeterminate structures. It begins by outlining the basic principles and definitions of the method, including stiffness factors, carry-over factors, and distribution factors. It then provides an example problem, showing the calculation of fixed end moments, establishment of the distribution table through successive approximations, and determination of shear forces and bending moments. Finally, it discusses extensions of the method to structures with non-prismatic members, including using tables to determine necessary values for analysis.

This document provides an overview of design in reinforced concrete according to BS 8110. It discusses the basic materials used - concrete and steel reinforcement - and their properties. It describes two limit states for design: ultimate limit state considering failure, and serviceability limit state considering deflection and cracking. Key aspects of beam design are summarized, including types of beams, design for bending and shear resistance, and limiting deflection. Reinforcement detailing rules are also briefly covered. Design examples are provided to illustrate bending and shear design of beams.

This document provides an overview of different seismic analysis methods for reinforced concrete buildings according to Indian code IS 1893-2002, including linear static, nonlinear static, linear dynamic, and nonlinear dynamic analysis. It describes the basic procedures for each analysis type and provides examples of how to calculate design seismic base shear, distribute seismic forces vertically and horizontally, and determine drift and overturning effects. Case studies are presented comparing the results of static and dynamic analysis for regular and irregular multi-storey buildings modeled in SAP2000.

This document summarizes the key aspects of flat slab construction and design according to Indian code IS 456-2000. It defines flat slabs as slabs that are directly supported by columns without beams, and describes four common types based on whether drops and column heads are used. The main topics covered include guidelines for proportioning slabs and drops, methods for determining bending moments and shear forces, requirements for slab reinforcement, and an example problem demonstrating the design of an interior flat slab panel.

- The document describes the design and detailing of flat slabs, which are concrete slabs supported directly by columns without beams. - Key aspects covered include dimensional considerations, analysis methods, design for bending moments including division of panels and limiting negative moments, shear design and punching shear, deflection and crack control, and design procedures. - An example problem is provided to illustrate the full design process for an internal panel with drops adjacent to edge panels.

This document discusses the design of two-way floor slab systems. It compares the behavior of one-way and two-way slabs, describing how two-way slabs carry load in two directions versus one direction for one-way slabs. Different two-way slab systems like flat plates, waffle slabs, and ribbed slabs are described. Methods for analyzing two-way slabs include direct design, equivalent frame, elastic, plastic, and nonlinear analysis. Design considerations like minimum slab thickness are discussed along with examples calculating thickness.

Content: -USD(Ultimate Strength Design) -Classification of beam with respect to design system -Assumptions -Evolution of design parameters -Moment Factors Kn,  -Balanced Reinforcement Ratio b -Calculating Strength Reduction Factor  -Calculating -Design procedure for Singly Reinforced Beam -Design procedure for Doubly Reinforced Beam -Design procedure for T-Beam -Appendix

This document discusses ductile detailing of reinforced concrete (RC) frames according to Indian standards. It explains that detailing involves translating the structural design into the final structure through reinforcement drawings. Good detailing ensures reinforcement and concrete interact efficiently. Key aspects of ductile detailing covered include requirements for beams, columns, and beam-column joints to improve ductility and seismic performance. Specific provisions are presented for longitudinal and shear reinforcement in beams and columns, as well as confining reinforcement and lap splices. The importance of cover and stirrup spacing is also discussed.

This document discusses T-beams, which are more suitable than rectangular beams in reinforced concrete. There are two types of T-beams: monolithic and isolated. It provides notations and code recommendations for T-beams from IS: 456. There are three cases for finding the depth of the neutral axis in a T-beam: when it lies in the flange, in the rib, or at the junction. An example problem is worked through to find the moment of resistance for a given T-beam section using the provided concrete and steel properties.

Introduction to Capacity-based Seismic Design by Dr. Naveed Anwar of Asian Institute of Technology (AIT), Thailand

This document provides an overview of design in reinforced concrete according to BS 8110. It discusses the basic materials used - concrete and steel reinforcement - and their properties. It describes two limit states for design: ultimate limit state considering failure, and serviceability limit state considering deflection and cracking. Key aspects of beam design are summarized, including types of beams, design for bending and shear resistance, and limiting deflection. Reinforcement detailing rules are also briefly covered.

This document describes research using neural networks to predict the propagation path of plastic hinges in moment resisting frames under seismic loading. Pushover analyses were conducted on various frame configurations to create a database for training a neural network. The neural network takes frame element stiffness values as input and outputs the plastic hinge condition at different nodes. Training results showed the network could accurately predict plastic hinge distribution and collapse mechanisms. Validation on additional frames found reasonable correlation between predicted and actual plastic hinge statuses. The research demonstrates neural networks may provide a useful tool for assessing frame post-elastic behavior and collapse mechanisms at the design stage.

This document reviews literature on using natural and synthetic fibers to modify the strength properties of concrete. It summarizes several studies that tested how bamboo, fiberglass, carbon fiber, and basalt fiber reinforcements impacted the bending strength, tensile strength, and deformation of concrete beams compared to steel-reinforced beams. The review found that fiber reinforcements can improve concrete strength characteristics but noted gaps in research on using fiber-reinforced polymer composites as the main reinforcement and on reinforcing hollow concrete columns.

This document discusses the history of structural analysis methods. It explains that statically indeterminate structures require analysis to ensure they have sufficient strength and rigidity. Two fundamental methods are described: force methods, which satisfy compatibility equations; and displacement methods, which satisfy equilibrium equations. Specific displacement methods discussed include the slope deflection method, which considers bending deformations, and the moment distribution method introduced by Hardy Cross, which is an iterative method for analyzing frames.

This document reviews research on the effect of moment capacity ratio (MCR) at beam-column joints in reinforced concrete framed buildings. It summarizes several studies that investigated how increasing the MCR, defined as the ratio of column moment capacity to beam moment capacity, improves structural performance during seismic events. A higher MCR promotes a strong-column weak-beam design that increases ductility and lateral strength while reducing structural damage and failure probability. Most codes recommend a minimum MCR of 1.0-2.0, but the ideal ratio may vary based on building design, geometry, and seismic zone. Nonlinear analysis shows higher MCR generally enhances displacement capacity and reduces fragility, helping structures better withstand earthquake forces.

This document summarizes a lecture on the design of reinforced concrete beams for shear. It addresses topics like shear stresses in beams, diagonal tension cracking, types of cracks, shear strength of concrete, web reinforcement requirements, and ACI code provisions for shear design. An example is also presented on calculating the required area of web reinforcement based on the code equations. The document provides information needed to understand and apply the design of beams for shear stresses.

This paper compares the seismic analysis of a G+11 square building and L-shaped building using time history analysis in ETAB 17.01 software. Different types of bracing systems are used, including X, V, inverted V, and diagonal bracing. The response of the buildings is compared in terms of displacement, base shear, and pseudo acceleration to determine which type of building and bracing system provides the minimum response. The L-shaped building with X bracing is found to have the minimum displacement, while the square building with X bracing has the minimum base shear and pseudo acceleration.

Today, retrofitting of the old structures is important. For this purpose, determination of capacities for these buildings, which mostly are non-ductile, is a very useful tool. In this context, non-ductile RC joint in concrete structures, as one of the most important elements in these buildings are considered, and the shear capacity, especially for retrofitting goals can be very beneficial. In this paper, three famous soft computing methods including artificial neural networks (ANN), adaptive neuro-fuzzy inference system (ANFIS) and also group method of data handling (GMDH) were used to estimating the shear capacity for this type of RC joints. A set of experimental data which were a failure in joint are collected, and first, the effective parameters were identified. Based on these parameters, predictive models are presented in detail and compare with each other. The results showed that the considered soft computing techniques are very good capabilities to determine the shear capacity.

This document summarizes a study on using frequency response methods to identify structural damage in layered composite materials. It proposes a new vibration-based technique that uses changes in the frequency response functions (FRFs) of an undamaged structure compared to a damaged one. Most reported works are based on changes in modal parameters, but this new method detects damage through existence, localization and extent using frequency response function curvature. It aims to establish an online damage identification method for laminated composites to address needs for health monitoring of composite structures, as damage alters their dynamic characteristics.

This document summarizes an experimental study on the flexural strengthening of continuous two-span unbonded post-tensioned concrete beams with end-anchored CFRP laminates. Five full-scale beams were tested: one control beam and four beams strengthened with CFRP laminates of varying widths and end anchorage configurations. The study found that CFRP strengthening increased the service load capacity more than the ultimate capacity. Proper end anchorage and installation of the CFRP laminates was important to achieve effective load transfer and prevent premature debonding failures. The strengthened beams exhibited higher stiffness and load capacity compared to the control beam.

1) The document presents the results of a linear and non-linear analysis of reinforced concrete frames with members of varying inertia (non-prismatic beams) for buildings ranging from G+2 to G+10 storeys. 2) Both bare frames and frames with infill walls were analyzed considering different beam cross-sections - prismatic, linear haunch, parabolic haunch, and stepped haunch. 3) The linear analysis was performed using ETABS and considered parameters like fundamental time period, base shear, and top storey displacement. The non-linear analysis used pushover analysis in SAP2000 to determine effective time period, effective stiffness, and hinge formation patterns.