Surakarta (24/10) Semarang Class I Railway Engineering Center (BTP Semarang), Directorate General of Railways of the Ministry of Transportation together with the Bridge and Road Tunnel Safety Commission (KKJTJ) of the Ministry of Public Works carried out technical assistance for the load test (loading test) of the Solo Balapan plot railway overpass - Kadipiro or commonly known as the Simpang Joglo elevated rail, Surakarta. This 1.8 kmsp railway elevated track is part of the construction of the Solo Balapan - Kadipiro - Kalioso double track train (10 kmsp). Specifically, load tests were carried out on a composite steel frame railway bridge structure with a total length of 270 m, with a main span of 130 m and 2 short (approach) spans of 70 m.

Present on this occasion, the Director of Railway Infrastructure, Hengky Angkasawan was accompanied by the Head of BTP Semarang, Rudi Pitoyo. Hengky said that the temporary test data showed quite good results towards the readiness of the elevated route operation plan. "Today static and dynamic tests were carried out, it can be seen that the temporary data is in accordance with the planning documents. KKJTJ also appreciates that the construction of this bridge is in accordance with the structure that has been determined," explained Hengky.Met at the testing location, Prof. Jamasri (KKJTJ member), explained that this loading test was carried out to test the characteristics of the bridge structure. “The load test is carried out by providing static and dynamic loads. Dynamic load tests are carried out using 2 (two) loading methods, namely the load generated via a shaker and the ambient load with a running locomotive. The dynamic and static tests this time deployed 6 (six) CC 201 locomotives (84 tonnes/unit) and 2 CC 300 locomotives (90 tonnes/unit) with a total weight of 684 tonnes which means it met 52.6% of the design load of 1300 tonnes for the load test single track elevated," explained Prof. Jamasiri.

The test results were obtained in the form of a vibration response which was then analyzed using Fast Fourier Transform (FFT) and Experimental Model Analysis (EMA) to determine the magnitude of the natural frequency and mode shape. "The results of the interim analysis show that the natural vertical frequency of the first mode is 1.63 Hz, this value is higher than the planning calculation, namely 1.34 Hz, which means that the bridge characteristics are stiffer compared to the planning," explained Prof. Jamasri.

The static load test was carried out by positioning 8 (eight) locomotives forward from Kadipiro Station towards Solo Balapan Station. The locomotive series stops in 12 stages, position ½ short span side of St. Kadipiro, 1 full short span side of St. Kadipiro, ¼ main span, ½ main span, ¾ main span, 1 full main span, position ½ short span side of St. Solo Balapan and 1 full short span side of St. Solo Racing.

 "Data collection while the dynamic and static tests were synchronous, the maximum deflection in the middle of the main span was recorded at 27.488 mm while the planner's calculation was 32.25 mm (the characteristics of the bridge are stiffer than the planner's calculations). After this the test consultants, the KKJTJ and BTP Semarang teams were present discussion for further analysis," he explained

Meanwhile, the Head of BTP Semarang, Rudi Pitoyo, said that BTP Semarang had completed the construction phase on the downstream route. Currently a series of tests have been and are being carried out so that this double track train can partially be operated immediately. "So far the progress in the field is according to the timeline, we have completed a Safety Assessment with the Safety Directorate, Operational Facility Testing in collaboration with the Railway Testing Center, then load testing, all to ensure the security and safety aspects of the track, buildings and railway operation facilities in accordance with Minister of Transportation Regulation Number 69 of 2018 "Concerning the Railway Safety Management System," said Rudi. 

"If later train operations can be carried out via the elevated track, this will really help speed up the construction of the underpass underneath. The construction of the Simpang Joglo railway flyover as well as the arrangement of the surrounding area is the Government's concrete solution to reduce congestion at Surakarta's busiest intersection. We want the movement of the people of Solo Raya to be smoother, more productive, there is no need for traffic jams anymore because here is the meeting point of 7 (seven) road intersections (2 national roads, 2 provincial roads, city roads and environmental roads) with active train lines that lead to Semarang and head to Adi Soemarmo Airport. "We are very grateful for the support of the people of Solo Raya who are willing to detour and adjust traffic flow during this construction," he concluded