CAREER EPISODES 1

Introduction

This career episode is to briefly describe my work duties and work place activities during the project of “***************”, from August 2002 to May 2003, when I was working as an assist structural engineer in Structure D&R Institute of *********************, this project is located in Beijing, China. This design project was started from August 2002 and was finished in May 2003, and the construction phrase was from August 2003 to May 2005, and now the building is in the operation.

Background

Nature of the project

The project of *****************” is a building complex which site occupied 31,100m2, the total building area is 280,000m2, and the highest towers are all have 23 stories and the cornice height is . The function of it is cover from office building, commercial building and hotel, to large-scale public bus-subway transfer station. The structure forms include frame-shearwall system and frame system, with multi-story basement. This building group includes four towers to and an annex, and there is a six stories annex which jointed three towers (No2~ into a whole.

Objective

My company’s work was to complete the whole design from area plan, landscape design, architecture design, structure design, mechanical, electrical, heat ventilating and air conditioning design, and plumbing design according to the site conditions and environment, as well as within the limited budget and schedule, After the design phase, we should instruct and oversee the construction, solve the unclear questions on the blueprints and even offer altered design to meet the required changes. As the construction completed, my colleagues and I also have the responsibility to conduct the check and accept.

My duties

As a structural engineer, I was one of main designers in our workgroup. I was in charge of the structure design work of and Tower. My work included: to establish the calculation model for the computer analyzing, to calculate the structural component, to draw the blueprints for the construction purpose, collate drawings with my colleagues.

My main duties were as follows:

1. Establish the calculation model for the computer analyzing and decide all the necessary factors to input the model into the computer.

2. Estimate the rationality of the calculation result after the computer analyzing.

3. According to the calculation result, offer revise suggestions to architects, mechanical engineers, electrical engineers, heat ventilating and air conditioning engineers and plumbing engineers, to make their designs meet the structural plan needs.

4. Draw the blueprints for the construction purpose which are following the conditions provided by architects and other professional engineers.

5. Check and collate drawings with my colleagues.

Organizational Structure

I was in the structure design department, the frame of the project organize was as follows:

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Fig. 1. Frame of the Project Organize

Personal Workplace Activities

Establish the calculation model.

1. The chief structural engineer and I decided which structure system should be applied in this project, establish the calculation model for the computer analyzing and decide all the necessary factors.

2. In this project, according to the state structural design codes and the experiences of my work, following the feasibility of the economy and the technology, I decided to apply the frame-shearwall system for this building complex. Generally to say, the two characteristics of structural behavior, respectively, involve resistance and displacement must satisfy the normal use conditions and the design codes. So, this kind of structural system has a good capability to resist earthquake action and wind force, it has a great rigidity and small displacement, at the same time, this kind of structure has a clear pressure transfer route, its design and construction technology is rather mature and we have a lot of relative experiences, that’s means the owner does not need spend extra cost on design and construction phrase. From what have been discussed above, the frame-shearwall system is an appropriate system for this project complex.

Calculation

1. The calculation included: dead loads and live loads calculation, the whole bearing capability, earthquake action, resistance for earthquake force, wind load, floor displacement, and the reinforcing steel bar configuration, etc.

2. The software I employed in this project were “PKPMCAD”-a kind of finite element analysis, design and drafting software package which is totally according with Chinese structural design and construction codes, “ETABS”-an integrated analysis, design and drafting of building software system developed by CSI, and MS-Excel.

3. For some manual calculations, I employed MS-Excel to get the result. I wrote some macro-sheets to assist my work. This kind of calculation is very suit for the checking computations and designing some components, and it really had a good effect. For example, when I design a floor slab, it could make me calculate the slab very fast and convenient.

Collate the calculation result

1. Check the calculation result. After the computer assistant calculation completed, I need to judge the result by some manual calculations and my prior engineering experience. If there was any improper situation, I would modify the correlative factors and the model or the sizes of the components to calculate it again, and feedback these amends to other professional engineers to modify the plan.

2. The collation included: period of the structure, earthquake model, earthquake force, structural displacement, reinforcing steel bars configuration, the ratio of the rigidity between every two floors. I also checked whether or not these results are over the limitations set by the construction codes or beyond the owner’s expectation.

Cooperate with architects and other engineers

Cooperate with other professional engineers is also an important process in the design phase. In this project, I also had to cooperate with other professional engineers. They were architects, mechanical engineers, electrical engineers, heat ventilating and air conditioning engineers and plumbing engineers.

I need to put forward some suggestions to these engineers to ask them adjust their plans to meet the structural needs, and, at the same time, they also gave me many requests to offer relevant conditions to satisfy their thoughts. These works were:

1. I established the structural model according with the architectural plan to conduct the computation, and though the calculation I could determine the structural plan and the sizes of the structural components, including walls, beams, and columns, to assure the bearing capability for its own weight, the earthquake action and other forces.

2. After I decided the structural plan and the sizes of the components I should provide these data to architects and mechanical & electronical engineers and HVAC engineers for the detailed architectural solution and mechanical solution

3. I discussed with these engineers about the feasibility of the design and we arranged the holes, gateways, tunnels, equipment installation stages, and equipment foundations in advance.

4. When all engineers and I confirmed the plan, I returned to the computer to modify and recalculate the model, to complete the whole calculation.

Complete the drawings

According with the formal plans provided by architects, mechanical engineers, electrical engineers, HVAC engineers and plumbing engineers, I began to make the drawings for the construction phrase. The software I used was AutoCAD R14. These drawings were the only legal documents to be carried out in the construction phrase.

1. According with the calculation result and the architecture plan, I setup the axis net unifying with the plan, and then, I draw walls, columns, beams and other structural components on the axis, to engender the floor plan. In the drawings, I marked all the orientations and the sizes of all the components, and I also indicated all the index numbers for where detailed drawings should be laid out.

2. Draw the detail drawings. These included the particular sizes, locations, steel bars placements of all the structural components and the notes of how to handle them.

3. Draw the cooperative drawings. The basement is where a big amount of pipelines and tunnels for all kinds of electrics, air conditionings and plumbing systems integrated and concentrated, so there were many holes needed to be drilled through the walls and beams, and some pits should be placed in somewhere of the foundation to collect the waste water. I had to set these holes and pits in advance to make sure that they would not affect the safe of the structure and reduce the cost for the owner.

4. Set up the hardware and equipment foundations beforehand for the installation of the equipments in the future.

Verify drawings

Verify the calculations and drawings mutually with other engineers, amend the possible mistake and examine whether the preset condition is consistent with other professional engineers’ work.

1. I verified the correctness and the rationality of the calculation scripts, the building calculation model, the parameters and coefficients and the settings of the calculation.

2. I verified the correctness of the drawings and the rationality of the design methods, as well as the contents of the drawings to make sure that they are consistent with the design and the construction codes promulgated by our government and the governing departments.

3. I checked whether or not could the design meet the construction requirements.

4. I discussed with other professional engineers, and verify mutually about the pre-reserved holes, equipment foundations, equipment installation stages, water collecting pits and so on, to make sure that they were all correctly laid out and noted on the drawings.

Example case 1

One of experiences of this project episode was the frame beams loads reducing calculation for the top slab of the underground parking lot. When I was conducting the calculation of the underground parking lot ceiling slab, I found that because the span of the beams was too long and the dead loads and the live loads were too heavy, the calculation result of the configuration of the reinforced steel bars was beyond the limitation of the design code, and at the same time, the distortion of the beams was over the limitation. This kind of condition means that if I applied the results of the calculations into the drawings directly, the seismic resistant performance of the structure would be very weak, and these beams and their columns would be suddenly destroyed without any prolongation.

I discussed this problem with my superior engineer and the architects, we all agreed that the loads of the slab should be reduced and I requested the architects to reduce the thickness of the soil placed on the top slab, and to modify the preset route of the fire trucks to cut down the loads. Secondly, I modified the beams layout, to meet the requirement of the design to apply a discount factor allowable to the Load Code For The Design Of Building Structure. By these efforts, we resolved this problem successfully at last. All the details of the design were according to the design codes and the sight of the ground did not affected.

Example case 2

Another is the calculation of the floor slab. To enhance the application effect, the architect didn’t allow the routine main beams between the columns. To ensure the net height of the owner’s requirement, meanwhile guarantee the bearing capacity and rigidity, which need reduce the dead weight, I discussed with the principal and owner to adopt hollow ceiling slab solution. Hollow ceiling slab solution is a new technology, which adopt column bearing solution, the principle of which is to fill in mineral wool fibre block to reduce the dead weight of the floor slab, which increase a bit the cost, yet it can ensure the internal net height of the building to be the largest extension. The solution was approved by the principal and the owner; and I solved the problem successfully

Summary

This design project was started from August 2002 and was finished in May 2003, and the construction phrase was from August 2003 to May 2005, and now the building is in the operation. The work finished by my design group and I, including the calculations, drawing blueprints and the cooperation with the constructors, was all within the schedule and the budget, as well as totally according with the design quality standards. Our work was praised by the owner and the constructors. In this section of my career, I not only applied my former experiences, but also adopted many experiences and ideas of my colleagues, at the same time, I completed my work through the learning of the up-to-date building technology, building materials and design theories, it was a kind of valuable wealth of my career.