To Analysis and Design of Steel Structures using TSD

1. Summarize your study for the bending moment, shear force and deflection diagrams for the elements of the model

AIM:- To summarize your study for the bending moment, shear force and deflection diagrams for the elements of the model

INTRODUCTION:- Bending moment, shear force and deflection diagrams are analytical diagrams used for the study of behaviour of a member element under loading conditions.

PROCEDURE:-

• Firstly, to create seismic load as per IS 1893 in the model. Go to seismic load in the load ribbon. Select seismic wizard.
• Select Code Spectra. Click Next.

• Set the basic information.

• Specify there is no structure irregularity in the model.
• In fundamental period, specify structure type as RC- Steel Composite.

• In seismic force resistance system, select Moment-Frame System as 1st type and Brace Frame System as 2nd type as shown below.

• Select the effective seismic load as shown below.

• Therefore, load combination are generated.
• In analyse tab, go to SETTINGS. Check the modification factors for steel and concrete as 1.

• Check Load combination generated.

• Once again, validate the model. Hence, no error.
• Go to analyse, pick 1st order linear. Select all the load combinations.

• On running the analysis, warning are shown in the solver mode in the project window of the result view.

• Check in overall displacement under positive service for maximum displacement.
• In the result view, highlight node for maximum positive displacement. This shows the node for maximum positive displacement. So we need to change member section.

• This shows the node for maximum positive displacement in the solver view. So this shows we need to change member section.

1. Deflection Diagram

• In result view, go to deflection under result tab. Select deflection for Z axis and we can see maximum deflection at highligted section.
• Picking the deflection in the result view, we can see maximum deflection along Z direction is 263mm (so we need to change the section).

• The deflection value can be texted which shows deflection value greater than 200

• In result view, go to ground floor in scene view. Toggle to 3D view. Select the effective seismic weight in load case.
• Pick deflection in result tab to see maximum deflection.

   

• Siince the deflection is high(ie, 204mm between grid line 1 and 2, 150mm between grid line 2 and 3 and 80 mm between grid line 3 and 4).Therefore, section of these members will be changed to reduce the deflection as per IS code.

     b. Bending Moment Diagram

• Go to result view, under result tab select Moment Major for 1st order results and turn off the deflection.
• Under loadcase combination in loading tab, select effective seismic weight. Therefore, maximum moment in this condition for entire structure is 535.17kNm.

• Select frame 1 from project window. Go to result view, under result tab select moment major for effective seismic weight load combination.
• Therefore, this bending moment diagram is for simply supported member.
• Hence, moment maximum is 217.43kNm.

• In frame 1, Moment major is maximum in the load combinations shown below, ie, maximum moment for this frame is 370kNm.

  

• Similarly, Select frame C from project window. Go to result view, under result tab. select maximum moment value for load combinations.
• Therefore, from bending moment of simply supported member, the maximum is 725.08 kNm.

• Similarly, check bending moment for rest of the frames to analyse the structure.

     c. Shear force Diagram

 

• To check shear force, select Frame C in result view.
• Select shear major in results for effective seismic weight load combinations where shear force is maximum at first floor in frame C(ie, maximum shear force is +- 167.51kN).

• Check maximum shear force for different loading conditions for frame C.

• Similarly, check for rest of the frames to find analysis Shear force.

     d. To analysis sway/ deflection along X direction

• Under result tab, select deflection in X direction for different wind loadcases.
• For Wind +Y+Cpi,

  

• it is seen that Wind+X-Cpi loadcase have maximum deflection along X axis as shown.

• Also, check for different load combinations.

     e. To analysis Axial force

• For frame C, Go to results, pick Axial force and gravity load(ie, DL+LL) to analysis axial force acting on columns and braces.

• Also, check for different load combinations. Therefore, load combinations with maximum axial force is shown below.

• Braces which takes compressive force is highligted in yellow colour.

RESULT:- Hence, summarized the diagram for bending moment, shear force, deflection and axial force for the model. 

 

     2. Based on the analysis design the members and outline the thought process in selecting the member sizes along with the foundation design

AIM:-  To design the members based on the analysis and outline the thought process in selecting the member sizes along with the foundation design

INTRODUCTION:-Each members in the model is needed to be designed according to the site condtions and loadcases. Designing of amember includes selection of member size, reinforcement required, grade of concrete and steel, etc. so as to transfer the load safely. Design is checked based on strength and serviciability.

PROCEDURE:-

Ground floor

• In result view, go to ground floor in scene view. Toggle to 3D view. Select the effective seismic weight in load case.
• Pick deflection in result tab to see maximum deflection.

   

• Siince the deflection is high(ie, 204mm between grid line 1 and 2, 150mm between grid line 2 and 3 and 80 mm between grid line 3 and 4).Therefore, section of these members will be changed to reduce the deflection as per IS code.

• In the ground floor, go to Structural view. Select the member to change the member section size in the property window.
• In the property window, change the member section from MB 250 to MB 600 and also deflection limit to 250 in all cases.

   

• Again run analyse in 1st order linear.
• Therefore, deflection in that member is reduced to 52mm.

• Again go to Structural view, select the member to check if satisfy the condition like Bending Moment, shear force, delection, etc

• Therefore, the member satisfy the moment major limit 0.895 and also all the design conditions as shown.

• Now, go to review view to change the properties of the following section.
• In the review view, section property of the changed section passes the design criteria as shown below.

• Similarly, change the properties of the failed section by copying its properties.

• In structural view, properties of the changed member statisfy the design condition and therefore, deflection value changes on the running analysis.

• Similarly, change the properties of the rest of section members that fail.
• Pick the first beam as shown, click on design member (static) which will automatically section.

• From the summary, MB 450 satisfy all the design conditions as shown.

• Select the member below the designed section and check its design condition.

• From the summary, MB 400 satisfy all the design conditions as shown. 

•  Therefore, we copy the properties of the first to members that fall on grid line 1.
• Go to review view, to copy the properties.

       

• Similarly, follow this for rest of the members and following members passes the design condition.

• Now, select the member on grid line A. Select design member(static)  and we will see member with MB 600 does not satisfy the design condition (ie, buckling lateral torsional).

         

• Now, go to property window turn on top and bottom flange restrain and design the member. Select Yes.

• Therefore,UB 610x 229x 140 satisfy the design condition like major moment limit of 0.91 and also buckling lateral torsion is fully retrained.

• Go to review view, Copy the properties to the member needed by selecting the source.

 

• Check the member in structural view to see if design criteria is staisfied.
• Therefore,in review view these members passes the design condition.

• Similarly, follow the same for rest of members.
• Therefore, we can see in the review view ,beam sections in ground floor passes on redesigning.

• Member selected which is shown below is fails at moment major

• Therefore, member section of UB 610x 305x 179 from UK which satisty the design condition.

• Run the model in 1st order linear anlaysis. Therefore, deflection in each member is reduced a shown.

• Similarly, carry out the same procedure in 1st floor. Check the deflection Z direction in the result view. 

1st floor

• Therefore, values is high in load combination shown below.

• GO to structural view, select the member to design it.

•  Right click to design the member(static). Therefore, member section is designed to MB 600 which satisfy all the design conditions.

• Similarly, design rest of the members.
• Therefore, X direction member beams are designed and checked. Hence, passes the design condition as shown.

 

• Similarily, redesigning members in y direction.
• Select the member to be designed and on designing the member section is Obtained as MB 600 but the section fails the design condition.

  

• Therefore, select the member section UB 610x 305x 179 which satisfy the design condition.

• Continue the same process for rest of the members.
• Therefore, in review view, after designing and checking the members all X and Y direction members satisfy the design condition.

• Run the first order linear analysis. Therefore, we can see deflection reduces in result view for 1st floor.

•  Now, go to top of roof beam level.
• Select the load combination with maximum deflection in the result view. Therefore, maximum deflection is 43mm.

• Now, go to structural view to check the member satisfy the design condition.
• Follow the same process as followed in ground and first floor.
• Therefore, all the members in top of roof level satisfy the design condition.

• Run analysis. Therefore, maximum deflection reduces from 43mm to 22mm.

To check the column

• Select frame 1 in the structural view. Select the column shown is figure to check its property. Therefore, member MB400 does not satisfy design condition.

    

• The buckling combined does not satisfy on providing MB 600 for the member.

 

• Therefore, select higher member section from UK which are universal columns, UC 254x 254x 107.

• Similarily, check for rest of the columns in frame 1. Therefore, column 2, 3 and 4 are provided with UC 254x 254x 132, UC 254x 254x 132 and UC 254x 254x 107 respectively and hence all these members satisfy the design conditions.
• Next, design members for sloping beam (Rafter beam). Therefore, MB600 is designed but it does not satisfy slenderness value.

• Therefore, provide higher section of beam of UC 203x 203x 86 and check the design condition.

• Similarly, follow the same process for the rest of the rafter beam and check its design conditions. Hence, all the beams, column and rafter beam passes the design condition as shown in the review view.

• Next, to check the design condition for bracing. Go to frame C, select the braces.
• Hence, the brace with section 75x75x8 does not satisfy the design condition.

• Therefore, provide bracing section of 180x180xx20 which satisfy the design condition. Hence, the slenderness limit is reduced to 0.991.

• Similarly, follow the same process and bracing size for rest of the bracings.

                     

                                                   FRAME C                                                                                                                                         FRAME G

• Run analysis and under result view, select Axial force under different load combinations to check for bracings.

    AXIAL FORCE FOR BRACINGS

• Now, go to 3D view in review view, we can see beams connecting the sloping roof, bracings on the roof and foundations are yet to be designed.

• Follow the same process for beams connecting sloping roof and bracing a done in the designs above.

PEDESTAL FOOTING DESIGN

• Select base level of the structure. Turn off the grid and construction line and supports.
• Check the design condition for pesdestal footing and concrete column of size 400mm x800 mm passes the design criteria.

   

• Here is the reinforcement calculation for 2nd pedestal footing

• This is loading analysis for footing selected above for DL+LL combination with axial force ranging from 644.68kN to 650.68kN.

 SLAB DESIGN

1. GROUND FLOOR 

• In the review view, Hide the steel beam, steel column, concrete column and steel braces from scene view.
• Pick the slab reinforcement under the review tab. Therefore, slab reinforcement of T10 150mm (524mm^2/m)

      ii. FIRST FLOOR

• Simillary, for first floor follow the same process as followed in ground floor.

FOUNDATION DESIGN

• Go to base level. Under foundation tab, select Pad Base Column.
• Pick isolated pad base location to create isolated pad base.

• The pad base is column has a size of 1.8m x 1.8m and a depth of 750mm.

• Right click on member to design. Therefore, member is automatically designed to size of 1.8m x 1.8m with overall depth of 400mm and grade of concrete M20. Allowable bearing capacity for this foundation is 250 kN/m^2. Hence, passes the design condition.

              

• Lets provide grade of concrete as M25 and check the design. Therefore, member satisfy the design condition.

• Similarly, design foundation members for rest of the columns with grade of concrete M25.
• Next, foundation has a size of 2.5m x2.5m x0.55m with maximum bearing capacity of 246.8kN/m^2.

  

• Continue to design rest of the foundations as designed above.

RESULT:- Hence, designed the members and outline the thought process in selecting the member sizes along with the foundation design based on analysis.