BIM Approach in a Metro Project: Cekmekoy – Sancaktepe - Sultanbeyli Metro Line


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Photo Courtesy of Tekfen Engineering

BIM Expertise for an Efficient Metro Project

Tekfen Engineering served as the designer of Cekmekoy - Sancaktepe - Sultanbeyli metro line in Istanbul, ensuring the efficient completion of the project under the leadership of its Metro Projects Group with BIM expertise.

Photo Courtesy of Tekfen Engineering

Up to 40 Years of Engineering Experience

Hundreds of engineers, architects and designers at Tekfen Engineering are divided into teams specialized in different construction fields. One of these teams is the Metro Projects Group at the Department of Infrastructure and Transport.

Aytan Ediz, Director of Infrastructure and Transport Projects, states that the metro projects designed for the Istanbul Metropolitan Municipality by Tekfen Engineering are carried out by the Metro Projects Group, which consists of engineers and architects experienced in Building Information Modeling (BIM) applications and familiar with the LOD 400 standards required by the Municipality. Emphasizing that they have 40 years of engineering experience in the construction industry, Ediz says: “Metro projects are the most challenging and complex of rail system projects. In order to complete the construction process successfully, it is essential to detect and solve all problems on a digital twin created with the BIM approach in the early stages,” pointing out the significance of the task undertaken by the Metro Projects Group. 

Photo Courtesy of Tekfen Engineering

A Team of Experts Focused on Metro Projects

Huseyin Aytug, Railway Systems Department Manager, states that the Metro Projects Group is primarily responsible for all design aspects of the Cekmekoy - Sancaktepe - Sultanbeyli metro project. Serving as the designers of the project, this team of about 60 people consists of experts and architects from all engineering disciplines. As the main designers, this team provides coordination with different subcontractors involved in the design and construction stages. Huseyin Aytug  says: “Our engineers and architects, who create a digital twin of the project with all its layers, use the most advanced BIM and document management systems.”

Autodesk Applications and Tools Used

“Our group uses Autodesk AEC Collection platform, which includes integrated BIM applications, and Autodesk Cloud Construction (ACC) for the designs of the project,” says Serdar Kaya, Metro Projects Group Leader. Kaya adds that they frequently use AEC software and tools, including Revit, Civil 3D and Navisworks Manage as well as Infraworks, Robot Structural Analysis and Desktop Connector, and Dynamo codes.

Additionally, Autodesk Cloud Construction infrastructure has enabled team members working in different locations to work on a single model in the cloud environment. Presentations for the Istanbul Metropolitan Municipality and project stakeholders are made on the same platform as well.

3D Models

“Creating reinforcement and formwork drawings in metro projects is a time-consuming and labor-intensive process,” says Kaya, and adds the following: “Having to study various design alternatives for the project in addition to the requirement of LOD 400 standards in the design prolonged the process even further. In order to make better use of time in the project, we made the most of the opportunities offered by technology. Accordingly, our engineers and architects from all disciplines designed 3D models in Revit.”

Photo Courtesy of Tekfen Engineering

Structural Discipline and Revit Models

Serdar Kaya points out that the structural discipline team models the reinforcements while creating the structural models in Revit, which streamlines geometry changes, material changes and reinforcement detailing drawings. The team also used Dynamo codes to speed up the process. Kaya says: “We created our own library for reinforcement drawings. Using Dynamo, we wrote a code that maps the reinforcement model elements, and produces reinforcement drawings based on this library. Thus, we prevented the need to take repeated measurements and create drawings from scratch after each change. This saved us serious time and labor.”

Photo Courtesy of Tekfen Engineering

Route Project in Civil 3D

The route project was carried out in Civil 3D by the route team. “Using the metro route project created by our route team in Civil 3D, we modeled all the metro tunnels and their superstructure elements in Revit,” says Baris Ozgurcan Pozanti, Cekmekoy - Sancaktepe - Sultanbeyli Metro Project Coordinator. These statements also reveal how the team ensures gradual interdisciplinary coordination with the BIM approach.

Clash Detection with Navisworks Manage

Baris Ozgurcan Pozanti, emphasizes that they divided the model elements into sets using the Navisworks Manage application, and used these sets in clash detection. Pozanti says: “In doing so, we were able to ensure control with varying precision and achieve optimum quality at different stages of the project.”

Photo Courtesy of Tekfen Engineering

Maximum Use of Revit in Architectural Design

Pozanti highlights that they made full use of Revit in architectural designs, and adds the following: “In Revit, we model every detail related to manufacturing in the CSS project. This provides us with great convenience in interdisciplinary coordination, especially in electromechanics. Most importantly, this method makes it possible to obtain 100% accurate measurements in all architectural details of the project.” 

Photo Courtesy of Tekfen Engineering

Shoring Elements Also Modeled in Revit

Pozanti, states that they modeled the station shoring in Revit by detecting the clashes with the surrounding structures. “By ensuring interdisciplinary coordination through this method, we prevented the shoring elements from damaging the tunnels, and any potential reconstructions.” says Pozanti, and emphasizes that the BIM approach is meticulously maintained at every stage of the project.

Comprehensive BIM Coordination

Pozanti says: “Basically, we have coordination models that bring together geometric architecture, structural, electrical-electronic and mechanical disciplines. We examine our coordination models in Navisworks and detect any clashes. This process enables us to see all intra- and interdisciplinary clashes. We submit the requirements for processes such as shifting or arranging elements to the teams according to their level of priority. 

This is the designer side of our coordination efforts. We also have to consult with the employer through the consultant and contractor. This is where the ACC cloud infrastructure comes in. The employer and the consultant navigate through the model in the ACC infrastructure and submit the revisions we need to make on the models.”

Streamlined Workflows with Dynamo Codes

Pozanti, further explains that in addition to the presentations in ACC, they share the most up-to-date models with the employer, the consultant and the contractor at the beginning of each week with their own add-in software. “As part of the project, we may receive specific requests from teams in architecture, mechanics or other disciplines,” says Pozanti, and explains how they are able to respond to these demands with Dynamo codes: “For example, we have Dynamo codes for processes such as arranging column numbers or showing the location of mechanical equipment passing through brick walls - so that, we aim to make business processes and workflows as easy and efficient as possible.” 

Photo Courtesy of Tekfen Engineering

Data Management with InfraWorks

The team also carries out the phase planning of the construction site in Revit. This is where the InfraWorks software comes in to combine and link the data. A workflow in which Revit, Navisworks and InfraWorks are used together enables us to make the most accurate design decisions. Baris Ozgurcan Pozanti says: “This offers high accuracy for observing the relationship between the construction site and the existing infrastructures, the planned technical or structural situation, temporary excavation support structures and permanent structures.” Stating that the site data received from the organizations generally have a low accuracy rate, Pozanti also points out that surprises may occur on site, and adds the following: “3D models save everyone a lot of time, both during site planning and in situations that require the displacement of the infrastructures which emerge after site planning. When we have models in every detail, the only thing we need to do is to process the site data received from the organization in 3D with Revit, and continue with the coordination from there. Since the necessary determinations are made through research excavations on site before production begins, it is possible to accurately revise the site data coming from organizations. They also get to update their data. While this method was requested by the Istanbul Metropolitan Municipality, we have now standardized it for our other projects as well.” 

Photo Courtesy of Tekfen Engineering

CSS Metro Line will be open to public in the first quarter of 2024

The first five of the eight stations in the project are expected to be open to the commuters of Istanbul in the first quarter of 2024. Director of Infrastructure and Transportation Aytan Ediz emphasizes that the engineers and architects in the Metro Projects Group rely on the expertise they have achieved in the use of technology and the technology infrastructure they have in order to properly fulfill their duties as the designers of the Çekmekoy - Santaktepe - Sultanbeyli project. Ediz says: “Autodesk plays a key role in making our teams’ technology expertise sustainable.”