” CEGE0009编程 辅导、 写作JavaCEGE0009 GSA AssignmentDec 2020 Page 1 of 6CEGE0009 Structural Design and AnalysisAssessment of an existing building using GSACoursework BriefLearning objectives:1. Practise using GSA modelling and checking FE (Finite Element) outputs2. Understand how a reinforced concrete frame is typically modelled with FE3. Understand how a Finite Element global structural model is used to obtain designforces of particular members4. Practise ultimate capacity calculations for RC members5. Depend understanding of Frame structural behaviour and checking results against adifferent programBackgroundFigure 1 shows a reinforced concrete frame which is the structural system supporting anexisting building in central London. The building was originally designed for residential usewhich means it was designed for a live load of 1.5 kN/m2. The building owner is nowcontemplating changing the type of occupancy of the building to commercial use.Figure 1. Reinforced Concrete FrameYour jobAs part of your tutorial group, you will be working as structural consultants to advise thebuilding owner (the client) on whether the proposed change of use is structurally safe or not.CEGE0009 GSA AssignmentDec 2020 Page 2 of 6As this is an existing structure, the beams and columns already have cross-section dimensionsand reinforcement detailing as given in Figure 2 and Table 1. Your task is to assess whetherthe current members have sufficient capacity to resist the new anticipated design bendingmoments and axial forces under the new loading condition following provisions as per BS EN1992-1-1:2004. The allocated structural properties (geometric and material) as well as the newimposed loads can be found in Table 1. Shear capacity and detailing will not be consideredbut a shear reinforcement diameter is provided so that the position of the bendingreinforcement can be calculated.As1 = 2H8As2 = 4H10As3 = 2H12Shear stirrups H8Reinforcement Strength,fy = 500 N/mm2RC specific weight: 25kN/m3Concrete Cover = 30mmFigure 2. Characteristics of All beam and column sections,further information on geometry and material properties of the section can be found in Table1GSA ModellingUsing Oasys GSA 9, you will build a wireframe model (i.e. made of 1D elements) of the wholeframe using beam elements throughout. You will use the frame dimensions and memberstructural properties allocated to your group (see table p3). As per usual practice, the steelbars are not included in FE models however the specific weight of reinforced concrete shouldbe used so that gravity loads include the weight of the steel reinforcement. The columns willbe clamped at their base.The slabs will be assumed to be 2-way spanning but will not be modelled explicitly but theirload (dead+live) will be imposed on the frame using the GSA functionality called area gridload (see step-by-step guide). This is effectively an external pressure applied over a specifiedarea. This area load is distributed on the adjacent supporting beams. The calculation is doneinternally by GSA using a standard tributary area method. Once you have identified the liveload intensity for your building type, apply that on the first two floor slabs and only half of thatvalue on the top floor slab as this is just a roof. For the slab dead load, assume reinforcedconcrete slabs with a thickness of 150 mm throughout.Distributed (line) loads of 4kN/m should be applied on all first and second floor beams toaccount for the weight of the infill walls within the frame (these are not shown in Figure 1).Pattern loading on the first and second floor slabs should be considered for the live load forload combination 3 (see below). For this small frame this can be done simply by changing themagnitude of the area live load on each slab manually.Wind load will be considered acting on the xz elevation only. The load will be applied as pointloads on that faade nodes and the magnitude of each load will be calculated by handCEGE0009 GSA AssignmentDec 2020 Page 3 of 6assuming that each node takes the resultant of the pressure on the tributary area of the faade(same method as column tributary area under gravity load).The model will be analysed Using a static, linear analysis. In order to identify the most criticaldesign internal forces that each member will experience, the following load combinationsshould be defined and run in the software (following the provisions of BS EN 1990:2002):1) Dead Load2) Dead Load + Live Load3) 1.35 Dead Load + 1.5 Live Load4) 1.35 Dead Load + 1.5 Wind Load5) 1.35 Dead Load + 1.5 Live Load + 0.75 Wind LoadMore specific tasks will be required when only the wind load is acting on the frame (no gravity).This loading scenario is unrealistic and unlikely to lead to critical design forces, it is useful forthe purpose of appreciating the magnitude and shape of the internal forces generated by windand to make it easier to check results by hand calculations.Although the deflected shape of the building gives some useful qualitative information andoften allows mistakes to be spotted, quantitative predictions of deflection with this type ofsimple RC model cannot be Trusted so no check on serviceability will be required.LinPro ModellingThese tasks illustrate how one program output (here GSA) can be checked against another(LinPro). LinPro is a very basic FE package that can only deal with 2D elastic moment-resistingframes. You can think of it as a very primitive GSA. It is quite basic in terms of graphicalinterface (and can be a bit buggy!) but the advantage is that a newcomer is less drowned intothousands of functionalities that are only useful for experienced practitioners. Once youvedone this youll hopefully appreciate that all FE packages are based on a similar conceptualskeleton (nodes, elements, materials, restraints, loads, analysis, and results). In terms ofstructural behaviour, this section aims to explain why it is ok to use gross concrete crosssectionproperties in a linear elastic FE analysis to calculate the internal forces. Build a LinPro model of one of the two (identical) xz frames under wind load only (forinstance). Compare results to relevant GSA outputs. If you have made no mistake, theresults should agree within ~1% relative error. Once your LinPro agrees with GSA, manually double the value of the concrete Youngsmodulus and rerun the model. Compare to previous bending moment and deflectionresults obtained with LinPro (with real E). Explain what you observe. Now calculate the uncracked second moments of area for the two types of membersincluding reinforcement (see separate handout). Update the LinPro model (original E)with these new values of I and Recalculate the internal forces. Compare previousresults and comment.CEGE0009 GSA AssignmentDec 2020 Page 4 of 6Deliverables per group:1. Report to the client (assumed to have some but limited understanding of structuralengineering)Should include: Brief intro Assessment methodology: incl. your modelling assumptions, loading scenariosconsidered, the rational basis for your capacity calculations. No generic waffle aboutFEM or RC design or any other kind. Summary table comparing calculated member capacities and critical design forcesobtained from GSA (specify the load case that cased it) Conclude with final professional advice to clientLength constraints: up to 2 pages, up to two graphs, up to two tables.2. Calculation Report Should include: Detailed hand-calculations of beam and column ultimate capacity Hand calculation of the wind loads (wind pressure then wind point loads as input loadsin GSA) Model Validation Checks:o Hand calculations of column axial forces and vertical reactions due to deadload only + comparison with GSA reactionso Lower and upper bound hand calculation of shear and bending moments at theends of the longest Beams under Load Combination 2 of the bending momentsat the ends and mid-span assuming (i) the end of the beams are pinned and(2) the ends are fully clamped. Comparison with GSA output (should be inbetween). Checks against LinPro and structural behaviour understandingInclude comparison tables and comments as specified in the task section.Format constraint: up to 6 pages, no GSA graphs allowed, only hand-drawn 2-D frames orsketches should be included as necessary to explain calculations and results. Hand-writtencalculations are fine. No appendix of any kind is allowed.3. GSA Model file in soft copy4. LinPro Model File (left with uncracked I values)CEGE0009 GSA AssignmentDec 2020 Page 5 of 6Table 1. Geometric and Material properties allocated to each groupColumn BeamGroup No.No. StoreyStorey Height (m)No. Bay in XBay Length in X1 (m)Bay Length in X2 (m)No. Bay in YBay Length in Y1 (m)Width (mm)Depth (mm)Width (mm)Depth (mm)Concrete StrengthClassWind Speed (m/s)Imposed LoadCategory*1 3 3 2 6.0 4.5 1 3.5 400 400 300 250 C40/50 1.3 Restaurant2 3 3 2 5.5 4.0 1 4.0 350 350 250 300 C35/45 1.4 Restaurant3 3 3 2 5.0 3.5 1 4.5 300 300 200 350 C32/40 1.5 Restaurant4 3 3 2 6.0 4.5 1 4.5 400 400 300 350 C30/37 1.3 Library5 3 3 2 5.5 4.5 1 4.0 350 350 250 300 C25/30 1.4 Library6 3 3 2 5.0 4.0 1 3.5 300 300 200 250 C30/37 1.5 Library7 3 3 2 6.0 3.5 1 4.5 400 400 250 300 C30/34 1.3 Classroom8 3 3 2 5.5 3.5 1 4.0 350 350 250 300 C32/40 1.4 Classroom9 3 3 2 5.0 4.5 1 3.5 300 300 200 250 C35/45 1.5 Classroom10 3 3 2 6.0 4.0 1 4.5 400 400 300 350 C40/50 1.3 Filing Storage11 3 3 2 5.5 4.0 1 4.0 350 350 250 300 C40/50 1.4 Filing Storage12 3 3 2 5.0 3.5 1 3.5 300 300 200 250 C25/30 1.5 Filing Storage13 3 3 2 6.0 4.5 1 4.5 400 400 300 350 C32/40 1.3 Dance Hall14 3 3 2 5.5 4.0 1 4.0 350 350 300 350 C25/30 1.4 Dance Hall15 3 3 2 5.0 3.5 1 3.5 300 300 250 300 C25/30 1.5 Dance Hall* According to National Annex (NA) to BS EN 1991-1-1:2002Assignment administrationTotal weight: 15% of CEGE0009 final markGroup formation:This assignment in to be performed with your tutorial group.CEGE0009 GSA AssignmentDec 2020 Page 6 of 6Assessment criteria:Report to client should be clear, professional and competent without beingoverwhelmingly Technical.Calculation report should be clearly presented, well explained, well justified andcompetent. FE results are sensibly checked and there is reasonably good agreement betweenhand estimates and GSA values. Demonstrate good agreement and understanding in LinProsection.Weight breakdown: Report to Client 25% Calculation report 75%QA Session 1 on Friday 8th JanQA Session 1 TBCSubmission Date: 12th Feb 2021 by 5pm.Submission process:Soft Copy Submission via Moodle Submission System (GSA Assignment Tab in CEGE0009Moodle Page)Upload one single zip folder per group. The folder should contain two separate files:1. Reports (.docx or .pdf)2. GSA Model (.gwb)3. LinPro ModelPlease make sure the Name of the zip folder and all it contains includes your Group No. (NOTstudent number or name).如有需要，请加QQ：99515681 或WX：codehelp
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