Surakarta – The elevated railway at the Surakarta joglo intersection is under construction under the supervision of the Class I Railway Engineering Center (BTP) Semarang. The process of developing the railway infrastructure is openly shared with railway stakeholders in the Knowledge Sharing activity of the Joglo Simpang Composite Steel Pipe Bridge Work and the Implementation of the Grade Of Automation (GoA) Level.

The event was held in the city of Surakarta on Thursday (23/2/2023) for presentation material, and the next day with a field visit to the development project site.

The Railway Care Center team took advantage of this agenda, to be present in person, to study how the elevated rail line was constructed.

The material presented became one of the inputs for the Baperka maintenance team to strengthen the management of infrastructure maintenance at the Railway Maintenance Office, in preparation for the development of a line of work in the field of maintenance of railway infrastructure.

The first day was the agenda for presenting material from experts in the field of civil engineering. There are four presentation sessions. The first session was filled by Ir. Arvila Delitriana, MT, a construction consultant from PT Raya Konsult, with the subject matter of Planning in the Work of a 270 m Composite Steel Pipe Bridge on the Simpang Joglo Elevated Railway Line.

The second session, with the theme of Fulfillment of Quality Control and Load Testing in the Implementation of the 270 m Span Composite Steel Pipe Bridge on the Simpang Joglo Elevated Railway Line, was delivered by Prof. Ir. Jamasri, Ph.D, professor of the Department of Mechanical and Industrial Engineering, Gadjah Mada University, Yogyakarta. The third session, discussing the Fulfillment of Quality Control and Load Testing in the Implementation of the 270 m Span Composite Steel Pipe Bridge on the Joglo Simpang Elevated Railway Line, was presented directly by the construction project contractor PT Wijaya Karya Industry and Construction, Joko Trisnanto, ST and Danang Wibowo, ST. And the last session, PT Len Railways System presenters, Ir. Zulham, S.T, IPM., ASEAN Eng, also discussed the Implementation of the Grade of Automation (GoA) Level.

The Knowledge Sharing material initiated by BTP Semarang, describes in full the stages of the construction of the flyover bridge.

The first session describes the civil engineering analysis review process, before the project is implemented. According to source, Arvina, the construction used is steel pipe with due regard to structural loading which refers to the AREMA MRE 2021 regulation and related regulations.

The graduate of the Bandung Institute of Technology (ITB) stated that he had calculated various technical aspects of loading, dead loads, live loads, shock loads, horizontal loads, including train lateral loads, brake and traction loads, long longitudinal rail loads, then wind loads, and also the earthquake load, along with the temperature change factor.

Steel pipe construction in buildings in Indonesia has never been used in bridge construction. "Foreign steel pipe construction is effectively used well in the oil and gas industry in the offshore area, seeing the function of the elevated rail bridge on the joglo crossbar, it is possible to use the steel pipe construction, of course after going through various layers of civil engineering calculation analysis," explained Arvina.

As the team leader, Alvina admits that she does not only consider technical aspects for the safety of the building, but also the aesthetic value in the building design. "If you look closely, the design of the bridge can be described in the form of half of the kawung batik pattern, as is the character of batik in Surakarta," said Arvina.

In general there are two groups of results of civil engineering studies on buildings, the first is the upper structure covering the pier including the pierhead of the building structure to support a series of steel pipes, and the second is the lower structure regarding determining the class of the site using stratigraphy to determine the profile of the soil conditions that will become the foundation of the building. "Considering that the surrounding environment is a busy residential area, a single pear is used to support the elevated rail frame," said Arvina.

In addition, the length of the bridge being built exceeds 100 meters, requiring special handling, one of which is the need to carry out a load test as a condition for obtaining a certificate of proper functioning. These provisions are contained in PUPR Ministerial Regulation Number 41 of 2015.

Based on these provisions, the load test was carried out by the PUPR Road Bridge and Tunnel Safety Commission. This became the common thread between the second material session and the first. When the first session describes the results of the study, the second material session is the next process that must be carried out so that the bridge gets a certificate of proper functioning.

The test, as explained by Prof. Jamasri, quality control of steel bridge works, including testing of basic materials to check the mechanical materials and chemical composition in them. Then also because it uses a steel frame, it is necessary to pay close attention to the details of the welding to be carried out, in the Welding Procedure Specification (WPS) language based on the AWS D1.5 guidelines, including checking using the Welder Qualification Test Record (WQTR) and Welding Performance Qualification Record (WPQR) mechanisms. for welding expertise personnel, through to joint quality control (NDT).

After review and testing, the next process was described in the third session, in the steel frame fabrication process of the bridge which was carried out at the PT Wijaya Karya Industri and Construction workshop in Majalengka. This facility is responsible for the process of forming steel pipes into several main parts, which later these parts will be transported using land routes with strict treatment procedures, until they arrive at the Surakarta Joglo crossbar project site.

Welding is not only carried out at the Majalengka workshop, but also carried out on the spot at the construction site, which is carried out by certified welding experts, and with the character of welding work at height.

The fabrication process uses methods according to work procedures in construction, accompanied by emergency response plan (ERP) procedures as a mitigation measure for work accidents in the field. The entire construction work process was explained in detail by the PT Wijaya Karya Industri and Construction team.

The final material in the fourth session is still related to railway infrastructure, namely the field of signaling. The elevated rail bridge built is possible for the development of automation for the movement of rail facilities that pass over it. In terms of space construction on the upper bridge building, it is still possible to add an LAA (Upstream Electricity) circuit, as part of a signaling device that leads to future train automation.

The working mechanism of railway transportation automation was explained by PT Len Railway System experts.

On the first day, the Baperka team and participants absorbed a lot of theoretical material which is the basis for the construction of flyovers. The next day the Baperka team was at the flyover construction project site. Before the group was invited to the construction area closer, the construction work team explained the Occupational Safety and Health procedures around the construction site, as a form of preventive effort to prevent work accidents in the field.

All participants wore project standard safety vests and helmets. Not far from the tent where the gathering was held, the participants could immediately see the construction of the pier/bridge piers that were already standing as a result of the casting work. Interspersed between the pier to the south, participants could see sections of steel pipes that would form the top of the bridge. Steel pipes are painted bright red to show the identity of the bridge later. The treatment on the pipe cross-section of the bridge was not arbitrary, it was seen that there was a dividing line that the group could not pass.

The review at the project site is useful for the Baperka maintenance team to map out the pattern of maintenance of infrastructure that will be developed in the future, when the bridge is functional and actively becomes a railroad operational route. By knowing the technical framework of the bridge, it will make it easier for the maintenance team to adjust needs according to the character of the infrastructure being built, one of which is a bridge with composite steel pipe construction such as the elevated rail line in the Surakarta joglo intersection area. (yogo)