My Happy Ending

Today, was the last day of my internship. It ended with a farewell tea session with my colleagues and supervisor.

Detailing and optimizing

Today, I did detailing for Main Truss A, Main Truss B, Main Truss C, Tie Truss 1, Tie Truss 2, Box Truss 1, Box Truss 2, Box Truss 3, Box Truss 4 and Box Truss 5 by seperating each of it to plan view, elevation view, side view and finally 3 dimension model. The purpose of detailing is to ease draught works.

Optimisation was conducted and lower tie truss requires to reduce in section size, hence, section assigned was changed.

A few senarios were required for the analysis. First senario, one of the support was fixed and the other was free to move. After conducting the analysis it yields huge deflection. Second senario, both of the supports were free to move. After conducting the analysis numerous member failed due to buckling checks, hence, correction was conducted on the particular member that failed.

An example of detailing for Box Truss 1

A different approach

I was taught by Mr. Lim to calculate the loads that act on UTAR Grand Hall. Based on architect's drawings. Top chord made up of roof tiles, asbestos, purlins and more. Therefore, the dead load assigned was 1.0kN/m^2 and the live load assigned was 0.25kN/m^2. On the other hand, the dead load assigned for bottom chord was 1.95kN/m^2 and live load assigned was 4.00kN/m^2. As a reason, catwalk hangs directly under the main truss. However, dead load assigned at Box Truss 1 was 3.5kN/m^2 and live load assigned was 3.5kN/m^2. Such a huge different was mainly due to fly galleries.

Loads were calculated based on Microsoft Excel. An example of calculation of loads that acts on top chord:

Nodal load = 1.0 * ((2.114/2)+(2.360/2))*8.0
= 17.896kN

Loads were assigned to Main Truss A.

The first analysis was conducted and it yields a deflection of 76.59mm. Moreover, numerous members failed for lateral torsional buckling and plane flexural buckling. Problem was rectified, it was found that top chord was too thick, hence the next analysis was conducted it is fine.

Today, loads were assigned to the 2 dimension model of Main Truss A, Main Truss B and Main Truss C. Loads were calculated with the help of Microsoft Excel. Then checks for axial stress, lateral torsional buckling and plane flexural buckling was conducted and section assigned was adequate. After that, loads for Main Truss A, Main Truss B and Main Truss C was assigned to the 3 dimension model. Lastly loads were assigned to rafter.

Loads were assigned to the 2 dimension model of Box Truss 1, Box Truss 2, Box Truss 3, Box Truss 4 and Box Truss 5. Loads were calculated with the help of Microsoft Excel. After that, loads for Box Truss 1, Box Truss 2, Box Truss 3, Box Truss 4 and Box Truss 5 was assigned to the 3 dimension model. Supports were assigned to the 3 dimension model. Checks for axial stress, lateral torsional buckling and plane flexural buckling was conducted and section assigned was adequate.

Loads were assigned to the 3 dimension model of Main Truss A

Loads assigned to the 3 dimension model of UTAR Grand Hall

The model of UTAR Grand Hall was completed

The model of UTAR Grand Hall continues, the ridge was modeled and combined with the previously modeled main trusses, tie trusses and box trusses.

The section assigned as below:

Ridge(RDG) : 457x152x52 I1(I-beam)

Ridge bottom chord : 200x200x50 S1(SHS)

Second day of the week, the rafter was modeled and assigned to the previously modeled UTAR Grand Hall.

The section assigned as below:

Rafter(RFT) : 356x171x45 I1(I-beam)

The legend of UTAR Grand Hall was made for future reference. I was then assigned by Ms. Winnie to prepare the next meeting minute which will take place on 5th July 2010. Once the model of UTAR Grand Hall completed, I was taught by Mr. Lim to calculate and assign loading to the model. This time around, the approach of assigning loading is different. Point load was used instead of Uniformly distributed load. As a reason, UTAR Grand Hall has a very complex roof truss

The completed model of UTAR Grand Hall

I am one step closer to the completed model

Today, the model of Box Truss 1, Box Truss 3 and Box Truss 5 was completed. All three box trusses consist of bottom chord(BC), top chord(TC), horizontal(H),vertical(V) and diagonal(D). However, Box Truss 5 consists of an additional middle chord(MC).

Section assigned as follows:

Bottom chord(BC) : 305x305x97(H-section)

Top chord(TC) : 356x368x129(H-section)

Middle chord(MC) : 356x368x129(H-section)

Horizontal(H) : 203x203x46(H-section)

Vertical(V) : 203x203x46(H-section)

Diagonal(D) : 203x203x46(H-section)

The following day, model of Box Truss 2 and Box Truss 4 was completed. Both of the box trusses consist of bottom chord(BC), top chord(TC), horizontal(H), vertical(V) and diagonal(D). Section assigned was same as Box Truss 1, Box Truss 2 and Box Truss 3.

Before the day ends. I was assigned by Ms. Winnie to write a meeting minute for the up coming meeting. Once the meeting minute was completed, I was told to fax a copy to the people invited.

All box trusses were completed

The cover page of meeting minute

Soil Investigation

Today, I was given a rare opportunity to witness soil investigation at Denai Alam. Transport was not provided and I was not guided. Lecture notes on standard penetration test and wash boring was revised the day before to gain insight on soil investigation. When I arrived, technicians were conducting boring for borehole 2 and so I witnessed boring and standard penetration test.

I was interviewed the day after I came back from site visit. As a result, my superior found out that I was not very clear about standard penetration test, hence, I will have to return to the site to obtain borehole log, photos and videos as evidence. Borehole 3 was witnessed.

A sample of borehole log

Main truss and tie truss tied a perfect knot

Advise was seeked from Mdm. Tan. She strongly recommends that I obtain the coordinate from Main Truss A, Main Truss B and Main Truss C. It was done by splitting the main truss into two, connected with trusses in between and lengthen the lower truss of Tie Truss 1 and Tie Truss 2. The changes of Tie Truss 1and Tie Truss 2 was made by Hameen. After that, it was merged with Main Truss A, Main Truss B and Main Truss C. As a result, it matches perfectly.

The formation of box truss was analysed. After that, we found that the formation of Box Truss 1 differs from Box Truss 3. In terms of diagonal member. Box Truss 1 made up of bottom chord(BC), top chord(TC), horizontal member(H), vertical member(V) and diagonal member(D). The model of Box Truss 1 was completed today. Just like before, Box Truss 3 and Box Truss 5 made up of bottom chord(BC), top chord(TC), horizontal member(H), vertical member(V) and diagonal member(D). Box Truss 3 and Box Truss 5 was completed by today.

The tie truss was combined with main truss

Box Truss 1 was modeled

The tie truss

Hameen has completed the model for Tie Truss 1 and Tie Truss 2. It was then combined with the main truss. As a result, it was found that the coordinate of the tie truss does not match the main truss.

As for tday, most of the time was spent on rectifying the problem arise. Finally, we found the culprit of the problem. We noticed that the provided architect's drawing on tie truss does not match the main truss. As a reason, the section of tie truss is larger compare to main truss. Hence, tie truss does not match main truss.

The drawing of tie truss was overlapped on main truss, it was found that tie truss has larger section.

The first step

The coordinate of Main Truss A, Main Truss B and Main Truss C was obtained by using autocad. First, the line of top chord, bottom chord, vertical member and diagonal member was offset. After that, the coordinate was obtained based on the intersection.

As for today, the model of Main Truss A, Main Truss B and Main Truss C was completed.

The coordinate of Main Truss A

Grand hall comes grand effort

Today, I was assigned a task to design UTAR Grand Hall. I have seen the incomplete model and analysis did by Mr. Lim himself. Instantly, it makes me thinks that this time around model and analysis of roof truss is not going to be simple as before.

The latest architect drawings with insufficient information and the passed yet incomplete model and analysis did by Mr. Lim was provided. Part of the project was delegated to Mr. Hameen one of the recently employed trainee from University Malaya. he will be modeling and designing the tie truss. Hence I will be modeling and designing the main truss.

As for today, I studied the drawings and passed analysis provided. After that, proper planing of the project takes place in order to reduce potential mistakes.

The plan view of UTAR grand hall

The cross section view of UTAR grand hall

The mansion

I was assigned by Mr. Lim to design the steel truss of Hajeedar bugalow. Loads were assigned as follow:

Main beam: Dead load = 18.55kN/m^2, Live load = 1.5kN/m^2
Secondary beam: Dead load = 4kN/m^2, Live load = 1.5kN/m^2
Wall: Dead load = 8kN/m

The second story was assigned with only uniform distributed roof load. Deflection was adequate. Lateral torsional buckling and plane flexural buckling was adequate as well.

An overview of Hajeedar bungalow's steel truss

The assigned dead load and live load

The deflected shape of Hajeedar bungalow's steel truss

Architects rule the game

Based on architect's request, verandah method was used to model the previously designed pedestrian bridge 2. Verandah method was meant by replacing the existing diagonal member with additional horizontal member.

After conducting the analysis based on verandah method, it was found that the section used was too huge. Therefore, the diagonal members were retained with the introduction of horizontal member to strengthen the pedestrian bridge.

Additional horizontal member was assigned with the absence of diagonal member

Verandah method was adopted with the existance of diagonal member to reduce the size of section used

A brand new approach

I offered my help to Ms. Aisyah to design and analyse the chalet that is located at Pulau Pangkor. It is a good opportunity to get myself expose and familiarise with ETABS. Architect drawings on plan view of ground floor, first floor, roof plan and elevation of the chalet was provided. As for today, only the grids and columns of the chalet was assigned, the beams for ground floor were also assigned there after.

The model and analysis of Pulau Pangkor's chalet continues today. The beam section, column section and slab thickness was assigned to the model. Based on British standard manual, the dead load of 9.3kN/m was assigned to the beam. On the other hand, the dead load assigned to the slab was 2.0kN/m^2, due to existance of Rendering, while cantilever slab has a dead load of 1.5kN/m^2. The live load that acts on the slab varries based on the usage, range between 2kN/m^2 to 4kN/m^2.

Today is the last day of 7th week, the model and analysis of Pulau Pangkor's chalet continues today. The third story which resembles the roof plan was assigned. The beam section was assigned. The column section was assigned. The slab thickness was assigned.

The model and analysis of Pulau Pangkor's chalet continues today. The previously assigned load was changed to:

Roof beam: Dead load = 1.5kN/m^2, Live load = 0.25kN/m^2

Roof slab: Dead load = 1.5kN/m^2, Live load = 1.5kN/m^2

Ground floor and first floor: Dead load = 1.5kN/m^2, Live load = 2.5kN/m^2

After conducting the analysis, errors were indicated at the angle columns and a few other beams located at the cantilever slab. Angle columns were changed to rectangular columns and larger beam section was assigned to failed beams.

The 3D view and plan view of Pangkor Chalet

The deflected shape of Pangkor Chalet

Pile cap design 2P400 and 7P300

Today, I was taught to design pile cap using truss method. There are limitation for truss method, where the number of pile used should not exceed 6 piles. Example and equation was provided to ease my learning process. Pile cap design for 2P400 was completed on the day.

Beam bending theory was taught to analyse pile cap that has more than 6 piles. Two examples were provided as reference. The first example was on pilecap design 7P300. The second example was on pilecap design 6P300. Both design and analysis was completed on the day.

An example of pilecap

The trouble goes on and on...

The amendments on UNIMAS roof truss continues, The model of the tie truss was constructed. It was then attached to the main truss. Additional trusses were constructed to support the metal roof that was on both side of the main truss.

Supports that resist vertical load were assigned at node 2,173,88,43,214,129,55,226,141,482,426,484,483,463 and 485. Dead load of 0.5kN/m^2, live load of 0.25kN/m^2 and wind load of 1.0kN/m^2 was assigned. The model and analysis was completed on the day.

The completed model and analysis of the UNIMAS roof truss was checked by Mr. Siva. Corrections listed as below was required:

-An additional member was required for the main truss to complete the triangular looks of main truss.
-I-beam was assigned to the trusses that supports the metal roof that is on both sides of the main roof.

-The beam sections were standardized by limiting the amount of beam sections used.

Corrections were completed on the day.

An overview of UNIMAS roof truss

The plane view of UNIMAS roof truss

loads were assigned to the roof truss

The deflected shape of the roof truss

Wrong assumptions

The analysis for pedestrian bridge was checked by Mr. Goh. Two mistakes were specified by him. First, the bridge was assumed to be straight instead of tilted, was completely wrong. Second, there is an additional loading on the bottom chord of the main truss, due to selfweight of the concrete and aluminum box.

First attempt was made to model the bridge based on the coordinate obtained from the autocad drawings provided. Sadly, it yields an irregular shape. Without much hesitation help was seeked from Mr. Lim. he advised me to make things simpler by rounding up the numbers and use cos-sin-tan method to obtain the coordinate. The corrections and analysis was completed on the day.

The end is futher than I thought

I was informed by Mr. Siva that the design of the UNIMAS roof truss has been revised based on the passed meeting with the appointed architect. The changes made are:

- The cross section of the main truss is triangular instead of a vertical line. However, the main truss that is in between the other two reamins as before.

- The fascia truss was eliminated.

- Formation of the tie truss changes as well. Top-chord of the tie truss extrudes 1m from the main truss, while bottom-chord extrudes 0.5m from the main truss.

- The existing canopy has been changed to metal roof.

- Tie-truss and I-beam was added to support the metal roof.

The drawings of the above changes were not provided by the architect. It was mere verbal instructions. As for today, I managed to model the triangular chaped main truss.

The main truss was changed to triangular shape

Pedestrian bridge

I was assigned by Mr. Goh to conduct an analysis on 2 of the pedestrian bridges that is made of steel, located at seksyen U8, Bukit jelutong, Shah Alam. I was then informed by Mr. Goh that the plan view of the provided drawings is up to date, while the elevation view of the provided drawing is not. However, the plan view of the pedestrian bridge 1 does not match the elevation view. As a reason. It was put on hold for a moment. The coordinate of pedestrian bridge 2 was located with help of Autocad.

The next day, the model of the pedestrian bridge 2 was constructed based on the coordinate obtained. Through my disappoinment, the bridge does not appear to be straight. Help was seek from Mdm. Tan, one of the reputable draughtsman in the consultant firm. I was advised by her to model the bridge as if it is straight, instead of tilted. The model of the bridge was completed on the day.

The analysis continues, dead load assigned is 2kN/m, while live load assigned is 4kN/m. The beam section assigned for top-chord and bottom chord of the bridge is SHS 150x150x8.0. On the other hand, the middle chord made up of SHS 150x150x8.0 and CHS 76x5.0. As for the column, beam section of CHS 324x6.0 was assigned. The supports at column resist translational and rotational movement. While, supports that is located at the end span of the bridge only resists vertical load to allowed expansion and compression of the steel bridge due to influences of heat.

After consucting the analysis. It yields a maximum deflection of 14.04mm at node 25. based on the analysis, plane flexuaral buckling and lateral torsional buckling is adequate. Checks for axial stress for each member is adequate.

An overview of pedestrian bridge 2

The deflected shape of the bridge

Analysis completed

Arrived early in the morning, segments of roof truss which consists of main truss, fascia truss and tie truss was combined. Beam section of 152x6.0 was assigned to the middle chord of the main truss. On the other hand, beam section of 102x3.0 was assigned to the top chord and bottom chord of tie truss and beam section of 76x5.0 was assigned to the middle of tie truss. Supports that resists vertical translational motion were located at node 114, 58, 2, 155, 99, 43, 167, 111 and 55.

The analysis yielded a maximum deflection of 21.94mm at node 189. Based on the analysis, plane flexural buckling and lateral torsional buckling check is adequate. Checks for axial stress for each member is adequate.

An overview of UNIMAS roof truss

The deflected shape of UNIMAS roof truss

Super structures

At the begining of the week. I was assigned by Mr. Siva to analyse a roof truss of a amphitheatre that is located at UNIMAS Sarawak. Coordinate of the roof truss was provided by the respective draughtsman Mr. Azizi. Dead load assigned was 0.5kN/m^2 and live load assigned was 2.0kN/m^2, while point load due to canopy was Fy = 100kN and Fx = 173kN. Wind load assigned was 1 kN/m^2.

As for today, Main truss, fascia truss, tie truss 1 and the tie truss 2 was modeled. Uniform distributed load was calculated for dead load, live load and wind load. It was assigned on the main truss and tie truss only, As a reason, tie truss only resists lateral stress. On the other hand, the loads due to the canopy was not able to calculate. Therefore, the load that acts on the roof truss was then estimated as Fy = 100kN and Fx = 173kN

The main truss

The fascia truss - The fascia truss and main truss may looks alike but they are different in terms of loads that acts on it

The tie truss that attaches to main truss - tie truss resists lateral stress