Instructor: Ella Li CSE E21 - 2022 CSE E21 Two Way Slab Lecture 6 3-D Elastic Analysis Course Coordinator: John Pao, P.Eng. Struct.Eng., S.E. Instructor: Ella Li, MASc, P.Eng, PE, SE Certificate Program in Structural Engineering – E21 Instructor: Ella Li LESSON OVERVIEW 1) FINITE ELEMENT ANALYSIS 2) ADAPT-BUILDER ~D 3) MOMENT REDISTRIBUTION Certificate Program in Structural Engineering – E21 SAFE RAM CONCEPT . No. 2 Instructor: Ella Li 1) FINITE ELEMENT ANALYSIS • 1.1 INTRODUCTION ↑β£ • 1.2 ADAPT-BUILDER • 1.3 SAFE • 1.4 RAM CONCEPT } these are Certificate Program in Structural Engineering – E21 Adapt FEM RC . Uses ELF . No. 3 Instructor: Ella Li 1.1 FINITE ELEMENT ANALYSIS - INTRODUCTION WHAT IS FE AND WHY • • • • Finite element analysis is a powerful computer method of analysis that can be used to obtain solutions to a wide range of one- two- and three-dimensional structural problems involving the use of ordinary or partial differential equations. For the majority of structural applications the displacement FE method is used, where displacements are treated as unknown variables to be solved by a series of algebraic equations. Each member within the structure to be analyzed is broken into elements that have a finite size. For a 2D surface such as a flat slab, these elements are either triangular or quadrilateral and are connected at nodes, which generally occur at the corners of the elements, thus creating a ‘mesh’. Parameters and analytical functions describe the behavior of each element and are then used to generate a set of algebraic equations describing the displacements at each node, which can then be solved. The elements have a finite size and therefore the solution to these equations is approximate; the smaller the element the closer the approximation is to the true solution. Certificate Program in Structural Engineering – E21 No. 4 Instructor: Ella Li 1.1 FINITE ELEMENT ANALYSIS - INTRODUCTION WHAT IS FE AND WHY • • • • FE methods generate numerous complex equations that are too complicated to be solved by hand; hence FE analysis was of interest only to academics and mathematicians until computers became available in the 1950s. The relative cost of computer hardware and software has reduced significantly over recent years and many engineers now have access to powerful software such as finite element (FE) analysis packages. it needs to be understood that FE is an elastic method, just like the elastic frame method described in the Codes. The use of FE analysis and design is certain to increase in the future. Currently it is a very useful method for slabs with irregular geometry, for dealing with openings in the slab and for estimating deflections. However, it is important to realize that the technique will not give lower design bending moments for regular grids. Certificate Program in Structural Engineering – E21 No. 5 Instructor: Ella Li 1.1 FINITE ELEMENT ANALYSIS - INTRODUCTION FINITE ELEMENT ANALYSIS ADVANTAGES • • • • • • It assists in the design of slabs with complex geometry where other methods require conservative assumptions to be made. It can be used to assess the forces around large openings. It can be used to estimate deflections where other methods are time-consuming, particularly for complex geometry. It can be used for unusual loading conditions, e.g. transfer slabs. The model can be updated should changes occur to the design of the structure. Computer processing speeds are increasing; reducing the time for analysis Certificate Program in Structural Engineering – E21 No. 6 Instructor: Ella Li 1.1 FINITE ELEMENT ANALYSIS - INTRODUCTION FINITE ELEMENT ANALYSIS DISADVANTAGES • • • • • • The model can take time to set-up, although the latest generation of software has speeded up this process considerably. The redistribution of moments is not easily achieved. There is a steep learning curve for new users and the modelling assumptions must be understood. Human errors can occur when creating the model; these can be difficult to locate during checking. Design using FE requires engineering judgement and a feel for the behavior of concrete. FE will not always return lower bending moments and deflections than would be obtained using traditional methods. Certificate Program in Structural Engineering – E21 No. 7 Instructor: Ella Li 1.1 FINITE ELEMENT ANALYSIS - INTRODUCTION FE SOLVERS – LINEAR ANALYSIS • • • • This is currently the most widely used method of FE analysis, but it is less sophisticated than non-linear analysis. Reinforced concrete (RC) is treated as an elastic isotropic material, which it evidently is not, and a number of assumptions have to be made to allow this method to be used. These assumptions in the modelling can lead to misunderstanding of the results. A linear analysis is more than adequate for carrying out a design at the ultimate limit state. The serviceability limit state can be checked by using ‘deemed to satisfy’ span-toeffective-depth ratios or by using conservative values for the elastic modulus and slab stiffness. Typically, 85% of elements are designed using the span-to-effective-depth rules and this is considered to be perfectly adequate for the majority of designs. Even the most sophisticated analysis only giveS an estimate of deflection in the range +15% to –30% . Certificate Program in Structural Engineering – E21 No. 8 Instructor: Ella Li 1.1 FINITE ELEMENT ANALYSIS - INTRODUCTION FE SOLVERS – NON-LINEAR ANALYSIS • • • Many FE packages are capable of carrying out non-linear (iterative) analysis, but this is useful only for reinforced concrete design where it can be used to model the cracked behavior of concrete. Non-linear analysis is used for RC design because as the slab is loaded it will crack and this affects its stiffness. The program carries out an analysis with uncracked section properties; it can then calculate where the slab has cracked, adjust the material properties and run the analysis again. This process continues until the variation in section properties between runs reaches a predetermined tolerance. A more sophisticated method is to also model the yielding of the reinforcement where it reaches the elastic limit. This requires advanced software and is generally used only for specialist situations. I For gravity design β 10 , analysis Reboot stops @ cracked section yielding Certificate Program in Structural Engineering – E21 No. 9 Instructor: Ella Li 1.1 FINITE ELEMENT ANALYSIS - INTRODUCTION FE SOLVERS – NON-LINEAR ANALYSIS • • • non-linear software will carry out an iterative analysis to determine an initial deflection; this will be based on initial, assumed, areas of reinforcement. Once the initial deflection has been determined, an assessment of the results should be carried out to decide whether the initial areas of reinforcement were appropriate. If not, they should be revised and the analysis re-run until there is convergence. It will be necessary to run the ULS model again with the correct reinforcement, because varying the area of reinforcement will alter the slab stiffness and hence the distribution of the moments (i.e. the stiffness at the supports will be reduced because of cracking and hence moment will be shed to other areas). An important aspect to achieving a realistic estimate of deflection is to consider the loading history for the slab; once the slab has cracked (and hence has reduced in stiffness) this will affect the deflection throughout the life of the slab. This should be considered in the model. Certificate Program in Structural Engineering – E21 No. 10 Instructor: Ella Li 1.2 FINITE ELEMENT ANALYSIS – ADAPT BUILDER ADAPT BY RISA https://risa.com/product s/adapt-builder • • • • 1 FOR FEM . FULLY INTEGRATED DESIGN FOR CONCRETE BUILDINGS. Seamless Modeling Workflow for Every Concrete Building. Efficiently analyze slabs or entire structures for the combined effects of gravity, lateral and vibration loading, utilizing true 3D finite element analysis, straightforward load takedown and realistic slab alignment. Whether you’re investigating an existing reinforced concrete slab or designing a multistory post-tensioned building, ADAPT-Builder allows you to control all aspects of design including cracking, long term deflections and punching shear, ensuring results are accurate and complete. Certificate Program in Structural Engineering – E21 No. 11 Instructor: Ella Li 1.2 FINITE ELEMENT ANALYSIS – ADAPT BUILDER ADAPT BUILDER OUTPUT Certificate Program in Structural Engineering – E21 No. 12 Instructor: Ella Li 1.3 FINITE ELEMENT ANALYSIS - SAFE SAFE BY CSI https://www.csiamerica.com/ products/safe • • • • • ANALYSIS AND DESIGN OF FLOOR SYSTEMS SAFE offers a single user interface to perform modeling, analysis, design and reporting. A new model explorer is available for quick access to objects, properties and forms. CSI solvers have been tried and tested by the industry for over 45 years. The SAPFire Analysis Engine can support multiple 64-bit solvers for analysis optimization and can perform both eigen analysis and Ritz analysis. SAFE is ideal for modeling foundations, basemats, and footings. Easily model soil supports and zero tension soil models with uplift analysis. Design strips are used to define how reinforcement requirements are to be calculated. SAFE can automatically define the strips for you, or you can define them yourself. Certificate Program in Structural Engineering – E21 No. 13 Instructor: Ella Li 1.3 FINITE ELEMENT ANALYSIS - SAFE SAFE OUTPUT might not good be M ¥¥¥¥%N ↓ term short OK ! Is cracked is good . deflection Certificate Program in Structural Engineering – E21 No. 14 Instructor: Ella Li 1.4 FINITE ELEMENT ANALYSIS – RAM CONCEPT RAM CONCEPT BY BENTLEY https://www.bentley.com/soft ware/ram-concept/ • • • • • THE GO-TO FOR CONCRETE SLAB AND FOUNDATION DESIGN Optimize the design of post-tensioning, reinforcement, and studded shear reinforcement for post-tensioned concrete floors using cloud-based optimization. Save engineering time by letting the optimizer sort through thousands of design alternatives and have confidence that your post-tensioned design has reduced material and labor costs. Design Raft Or Mat Foundations using soil springs and a zero-tension analysis. Confidently complete your designs with the extensive support of international standards. Design And Analyze With Finite Elements. Complete building analysis, design, drafting with finite element analysis. Reduce time spent waiting for results with fast solvers. Analyze Deflections For Time-Dependent Effects Certificate Program in Structural Engineering – E21 No. 15 Instructor: Ella Li 1.4 FINITE ELEMENT ANALYSIS – RAM CONCEPT RAM CONCEPT OUTPUT Certificate Program in Structural Engineering – E21 No. 16 Instructor: Ella Li 2) ADAPT BUILDER • 2.0 SOFTWARE INSTALLATION • 2.1 GEOMETRY using • 2.2 MODEL SETUP Eg • 2.3 LOADS . known Use DDM check Example . and with software • 2.4 MODELING • 2.5 ANALYTICAL TOOLS • 2.6 DESIGN OUTPUT Certificate Program in Structural Engineering – E21 No. 17 Instructor: Ella Li 2.0 ADAPT BUILDER - SOFTWARE INSTALLATION LICENSE FOR SEABC E21 PARTICIPANTS • Software download: https://secure.risa.com/index/downloads Register for ADAPT-Builder License Certificate Program in Structural Engineering – E21 RISA Customer Portal No. 18 Instructor: Ella Li 2.0 ADAPT BUILDER - SOFTWARE INSTALLATION INSTALLATION Licensing Type Certificate Program in Structural Engineering – E21 First Time Launch Software No. 19 Instructor: Ella Li 2.0 ADAPT BUILDER - SOFTWARE INSTALLATION LAUNCH SOFTWARE 7. PP0R RC design . Launch Software Certificate Program in Structural Engineering – E21 No. 20 Instructor: Ella Li 2.0 ADAPT BUILDER - SOFTWARE INSTALLATION RESOURCES User Manual https://risa.com/risahelp/adaptbuilder/index.html# Home.htm?TocPath=_____1 Slab Design Tutorial https://risa.com/risahelp/adaptbuilder/Content/Tuto rials/ADAPT-Builder%20MultiLevel%20Tutorial_05052022.pdf https://risa.com/risahelp/adaptbuilder/index.html#T utorials/ADAPT-Builder%20Multi-Level-Tutorial.zip YouTubeTutorial https://www.youtube.com/playlist?list=PLYrSU5MZrOnRu0XwKUlY0JR1hGS_P1ez Certificate Program in Structural Engineering – E21 No. 21 Instructor: Ella Li 2.0 ADAPT BUILDER – SOFTWARE INSTALLATION MAIN USER INTERFACE 1. 2. 3. 4. 5. 6. 7. Certificate Program in Structural Engineering – E21 Quick Access (toolbar) Level Tools (toolbar) Message Bar Quick Access Tools (toolbar) Status Bar - Model Information Results View (Result Display Viewer panel) Properties/Colorize/ Visibility (panels) No. 22 Instructor: Ella Li 2.1 ADAPT BUILDER – STRUCTURE GEOMETRY CONCRETE HANDBOOK EXAMPLE • EXAMPLE MODIFIED FROM CAC CONCRETE HANDBOOK Example ¥1 " Certificate Program in Structural Engineering – E21 No. 23 Instructor: Ella Li 2.2 ADAPT BUILDER – MODEL SETUP GEOMETRY • Method #1 Creating Gridlines: two options for creating gridlines. – Using the Wizard – Creating User-Defined gridlines. • Method #2 Import CAD File Certificate Program in Structural Engineering – E21 No. 24 Instructor: Ella Li 2.2 ADAPT BUILDER – MODEL SETUP REFERENCE PLANE By default, a new file in ADAPT-Builder has three reference planes: • Bottom Plane • Current Plane • Top Plane. µ " :* :* or " µ Certificate Program in Structural Engineering – E21 No. 25 Instructor: Ella Li 2.2 ADAPT BUILDER – MODEL SETUP MATERIAL PROPERTIES - CONCRETE • • software gives Compressive strength fc’ = 25 MPa you default Modulus of Elasticity (CSA A23.3-14 CL. 8.6.2.2) (Eq. 8.3) γπ 1.5 2300 = 3300 25 + 6900 × 2400 1.5 2300 vaβ³ only • πΈπ = 3300 ππ′ + 6900 × • Modulus of Rapture of Concrete (CSA A23.3-14 CL. 8.6.4) (Eq. 8.3) • ππ = 0.6λ ππ′ = 0.6 × 1.0 × 25 = 3.0 πππ Certificate Program in Structural Engineering – E21 . = 24,943 πππ No. 26 Instructor: Ella Li 2.2 ADAPT BUILDER – MODEL SETUP MATERIAL PROPERTIES - REINFORCEMENT • Specified yield strength of the reinforcement fy = 400 MPa Certificate Program in Structural Engineering – E21 No. 27 Instructor: Ella Li 2.2 ADAPT BUILDER – MODEL SETUP DESIGN CRITERIA • Design code: CSA A23.3-14 - check all tubs •÷:;;÷÷÷ more • tower !¥m or Certificate Program in Structural Engineering – E21 No. 28 Instructor: Ella Li 2.2 ADAPT BUILDER – MODEL SETUP DESIGN CRITERIA \ Certificate Program in Structural Engineering – E21 No. 29 Instructor: Ella Li 2.2 ADAPT BUILDER – MODEL SETUP DESIGN CRITERIA Certificate Program in Structural Engineering – E21 No. 30 Instructor: Ella Li 2.2 ADAPT BUILDER – MODEL SETUP DESIGN CRITERIA Certificate Program in Structural Engineering – E21 No. 31 Instructor: Ella Li 2.3 ADAPT BUILDER – LOADS LOAD CASE AND LOAD COMBINATION Certificate Program in Structural Engineering – E21 No. 32 Instructor: Ella Li 2.4 ADAPT BUILDER – MODELING MODELING SLAB -0 I the corner should the OR Draw not @ Gt change coordinate first CAD in Certificate Program in Structural Engineering – E21 No. 33 Instructor: Ella Li 2.4 ADAPT BUILDER – MODELING MODELING COLUMN :÷ :O above & below . @ properties ↑ You thou Id " have COLUM 2# type You • not ¥0m • ment . Do Not to Certificate Program in Structural Engineering – E21 use MY Rotate COLUMNS No. 34 ° Instructor: Ella Li 2.4 ADAPT BUILDER – MODELING MODELING COLUMN – COPYING VERTICALLY bottom top @ of Certificate Program in Structural Engineering – E21 Stato No. 35 Instructor: Ella Li 2.4 ADAPT BUILDER – MODELING MODELING METHOD – IMPORT CAD/DXF • • STEP 1: Go to File → Import → DWG STEP 2: Transforming DWG Entities into ADAPT-Builder Model Objects Certificate Program in Structural Engineering – E21 No. 36 Instructor: Ella Li 2.4 ADAPT BUILDER – MODELING TOP FRONT VIEW Certificate Program in Structural Engineering – E21 No. 37 Instructor: Ella Li 2.4 ADAPT BUILDER – MODELING VERIFY MATERIAL PROPERTIES colour coded material properties Certificate Program in Structural Engineering – E21 No. 38 Instructor: Ella Li 2.4 ADAPT BUILDER – MODELING ESTABLISH COMPONENT CONNECTIVITY TOOL relative ;¥hmnthat ¥ to me µpets . In:{ Certificate Program in Structural Engineering – E21 No. 39 Instructor: Ella Li 2.4 ADAPT BUILDER – MODELING MESHING THE MODEL Certificate Program in Structural Engineering – E21 No. 40 Instructor: Ella Li 2.4 ADAPT BUILDER – MODELING ANALYZING THE MODEL check deflected Shape check moment diagrams check Reaction @ column Certificate Program in Structural Engineering – E21 . No. 41 Instructor: Ella Li 2.4 ADAPT BUILDER – MODELING MODEL VERIFYING - SLAB DEFORMATION (SELF-WEIGHT) chelK# :É↑" ¥we deported shape Certificate Program in Structural Engineering – E21 No. 42 Instructor: Ella Li 2.4 ADAPT BUILDER – MODELING MODEL VERIFYING - SLAB DEFORMATION (SELF-WEIGHT) • CHECK COLUMN AT GRIDLINE D&3: π = 24 × 0.25π × 6.6π × 6.7π + 12.71 = 278.0 ππ c.net#J :* ::: *important Weight of column column .. toe stiffness Certificate Program in Structural Engineering – E21 No. 43 Instructor: Ella Li 2.4 ADAPT BUILDER – MODELING APPLY GRAVITY LOAD TO THE MODEL • SLAB UNIFORM LOAD – Superimposed Dead Load SDL = 1.0 kN/m2 – Live Load LL = 1.9 kN/m2 for Residential Floors • CLADING LINE LOAD must the select before slab How ? ,↓Y¥%ed Certificate Program in Structural Engineering – E21 No. 44 Instructor: Ella Li 2.5 ADAPT BUILDER – ANALYTICAL TOOLS SUPPORT LINES AND SPLITTERS • • • ≤ design strip . better manage If you'd like to hasten the design process in ADAPT-Builder, each slab must be subdivided into multiple design strips associated with a specific design criterion; (two-way slab, one-way slab, or beam) for two characteristic directions of the slab, X and Y (these directions do not have to align with the global X and Y axes). These strips are further sub-divided into design sections for the purpose of finding design actions, stresses, reinforcement, and more. You have complete flexibility and control over the location of design strips and the density and distribution of design sections. Splitters can be used in conjunction with support lines to give the user more control over the tributary generated by the program. Refer to the Splitters topic for more information on using splitters to limit the tributary width of the support line tributary. Learn main advantage 0g ADAPT ↓:[Ignores.→:÷:*:* over SAFE fine Certificate Program in Structural Engineering – E21 No. 45 Instructor: Ella Li 2.5 ADAPT BUILDER – ANALYTICAL TOOLS SUPPORT LINES L_4aLUMNSTR β³ steb create step support lines How ≤ Advantage ADAPT to edit suppot line 9 . 0 :* . support "" lines are 4h ships . // qq.eyj-my .IT#IIpp0rts :* ÷ . live ¥ :* short Certificate Program in Structural Engineering – E21 No. 46 Instructor: Ella Li 2.5 ADAPT BUILDER – ANALYTICAL TOOLS MIDDLE STRIP ? β³ what is this the support points β³ divide in further µm%%α΅emidβ to create middle strip Certificate Program in Structural Engineering – E21 No. 47 Instructor: Ella Li 2.5 ADAPT BUILDER – ANALYTICAL TOOLS DESIGN STRIP Certificate Program in Structural Engineering – E21 No. 48 Instructor: Ella Li 2.5 ADAPT BUILDER – ANALYTICAL TOOLS ANALYZE THE SLAB Certificate Program in Structural Engineering – E21 No. 49 Instructor: Ella Li 2.6 ADAPT BUILDER – DESIGN OUTPUT MOMENT CAPACITIES STEP Certificate Program in Structural Engineering – E21 #1 No. 50 Instructor: Ella Li 2.6 ADAPT BUILDER – DESIGN OUTPUT MOMENT CAPACITIES Certificate Program in Structural Engineering – E21 No. 51 Instructor: Ella Li 2.6 ADAPT BUILDER – DESIGN OUTPUT MOMENT CAPACITIES – MOMENT DEMAND Certificate Program in Structural Engineering – E21 No. 52 Instructor: Ella Li 2.6 ADAPT BUILDER – DESIGN OUTPUT MOMENT CAPACITIES – COMPARISON WITH EFM Certificate Program in Structural Engineering – E21 No. 53 Instructor: Ella Li 3) MOMENT REDISTRIBUTION • 3.1 CODE OVERVIEW Certificate Program in Structural Engineering – E21 No. 54 Instructor: Ella Li 3.1 MOMENT REDISTRIBUTION – CODE OVERVIEW CSA A23.3-14 Certificate Program in Structural Engineering – E21 No. 55 Instructor: Ella Li 3.1 MOMENT REDISTRIBUTION – CODE OVERVIEW CONCRETE DESIGN HANDBOOK Certificate Program in Structural Engineering – E21 No. 56