Tekla Structures helps to gain efficiency in Combined Cycle Power Project

L&T-S&L, an engineering and consultancy firm in the power sector, brings together the strengths of construction conglomerate Larsen & Toubro Ltd (L&T) and Sargent & Lundy LLC – USA, a global consulting firm in power industry. This synergy has enabled the company to consistently deliver technically sound and operationally efficient solutions like project management consultancy, detailed engineering, owner engineering and lender engineers to various domestic and international clients. Further, L&T-S&L has considerable expertise in detailed engineering for various gas-based, coal-based and solar-based projects which include detail designing of various critical facilities like STG building, steam or gas turbine equipment foundation, etc.

Seizing the opportunity by overcoming challenges
L&T-S&L was entrusted by an EPC company based in the Middle East with detailed engineering of a combined cycle power plant in the region. The company’s scope included detailed designing and preparation of foundation general arrangement drawings as well as bar bending schedule (BBS) of the steam turbine generator foundation which is the most critical part of a power station. Considering the magnitude of load of electricity producing equipment foundation i.e. the steam turbine generator foundation, the scope became wider and the project in turn, rendered even more challenging.

Further, the project presented other challenges including a mandate for BBS, which is usually managed by an off-site execution management team. Considering the criticality and complexities of steam turbine engine’s foundation in terms of size, geometry, numerous openings, embedment and large density of reinforcement bars in concrete elements, it was included in the company’s scope of work. Besides, delayed arrival of input for machine foundation left no room for any mistake or rework and completing the project within the given time frame thus became quite demanding. Amongst other construction challenges, placement of reinforcement in large concrete mat and its blocks with multiple embedded parts, requirement of big size cut-outs in wall as well as slab, etc. were the significant ones.

“We have usually avoided including BBS in our scope of work, anticipating a lot of manpower requirement and hassle. The confidence we have gained using Tekla for such a complex foundation has now encouraged us to include BBS for the entire project. Our customer has positively responded to the outcome and is going to consider the full scope in future projects. I am happy to share that this experience has spread positive spirit among our users and the customer, and there is additional enthusiasm to provide end to end solutions at one stop,” says Jignesh V Chokshi, Senior Deputy General Manager, Engineering.

Zero-error project is now a reality
Adoption of Tekla software resolved the complexities attached with the foundation geometry, size of concrete elements and amount of reinforcement to be placed in vicinity of many openings and embedment. Graphical interface, intelligent data, accurate BBS and material management offered by Trimble India’s flagship software, Tekla Structures enabled the smooth execution of the entire work, right from making geometry of concrete, modelling of embedded parts (of many complex items), modelling of variety of reinforcement and seamless connection between drawings and modelled items.

Recalling the project experience, Chokshi says, “As Tekla provides graphical interface for reinforcement placement, customisable bar numbering, accurate bar lengths, variety of material and reinforcement reports and seamless transfer of modelled information to various drawings in shortest time, the reinforcement with different colours and capability to share the model with site team have helped a lot during preparation, review and execution of this complex task.”

One of the most challenging parts of the entire project was the BBS which was easily surmounted by implementing Tekla software in the process. Here are the ways how the software benefitted the team:

Zero RFI
Tekla Software itself generated BBS layout drawing as well as table with bar type, length and its shape. Therefore, manual interface to integrate bar shape, length and layout was avoided. This resulted in zero errors and saved time to check the rebar shape, size or length.

Instant drawings
Tekla generated the rebar detailing section at required locations. Therefore, it was helpful to place “n” numbers of Tekla generated sections. In fact, based on site demand, additional sections were produced with almost no effort or time.
Easier site coordination in 3D
Tekla Software had better and understandable approach in anticipating rebar detailing at penetrations, which saved time and facilitated easier on-site execution.

With Tekla Structure, saving time and effort is easy and real
The numerous benefits that Tekla Structures brought to the project can be categorised both quantitatively and qualitatively. Quantitative benefits included saving man-hours and time, greater cost efficiency due to insignificant rework, material savings, on time or ahead of time project completion, etc. According to Chokshi, there is nearly 35 per cent reduction in effort over manual preparation of foundation general arrangement drawing and preparation of bar schedules. Additionally, the software facilitated completion of the project within the specified timeline with savings of around 3-4 weeks.

On the other hand, the qualitative gains of using Tekla Software included ease of project execution and management, reduced wastage and seamless collaboration among different stakeholders. Visual interface improved placement of multiple bars of complex shapes, curtailing bars at openings and embedment. Preparation and review of entire foundation geometry and reinforcement details with graphical interface turned out to be a seamless task. Ease of modelling rebar and accuracy in BBS for shape, quantities, etc. emerged as the biggest plus factor and most appreciated feature by the project team.

24