A. HISTORY
The Bantar Suspension Bridge was the first suspension bridge built in the Dutch East Indies at that time. This bridge is a connecting infrastructure that crosses the Progo River to connect Kepanewon Sentolo, Kulon Progo Regency to the west and Kepanewon Sedayu, Bantul Regency to the east.
Construction of the Swallow Bridge It was proposed in 1912 by Resident Djokjakarta Jacob Hendrik Liefrinck to be built in the Sentolo area. The initial proposal submitted an estimated construction cost of f156,000 Gulden to Burgerigke Openbare Werken (B.O.W.). This bridge was then designed by Th. E. Veer, architect of B.O.W. during 1915-1916 with construction costs reaching 1150,000 Gulden. At this planning stage, the Yogyakarta Sultanate is willing to contribute half of the construction costs, namely f 125,000 Gulden. This is considering that the construction of the Bantar Suspension Bridge has an important role for economic development in the Yogyakarta region.
In 1920, there was a change in the construction budget to f415,900 Gulden. Through Dutch Hindle Government Decree No. 32 dated May 1, 1920 the financing was borne by the government with a constant contribution from the Yogyakarta Sultanate (125,000 Gulden. In 1920 work on the construction of the Bantar Suspension Bridge was also started, but then stopped in 1921 due to the state's financial difficulties at that time.
In 1925 the bridge construction work resumed. The substructure work (construction of foundations and bridge piers) was tendered to Nederlendsche Aonnemingsmootschoppij (N.E.D.A.M.) which was completed in October 1927 at a cost of 229,000 Gulden. While the construction of the superstructure was carried out by the Werkspoor N.V. factory. in Utrecht at a cost of (221,000 Gulden. The steel material for the bridge structure was transported by ship and arrived at Cilacap Port in April 1928, then transported by train to Sentolo and Sedayu Stations. The superstructure construction assembly was carried out in August 1928 until finally the construction of the Banter Bridge was completed and was inaugurated on June 17, 1929. The entire development process was headed by engineer J.A. Verhoog with direct supervision from B.O.W
At the time of its inauguration, this bridge was given the name: Gouverneur Jasper-brug. The name was taken from Johan Ernst Jasper, the first governor of Yogyakarta during the 1928-1929 term. Previously J.E. Jasper has held the position of Resident in Yogyakarta since 1926 (Starting on December 19, 1927 the administrative status of the Yogyakarta region as a residency was upgraded to a province). During the War of Independence (1948-1949) the Bantar Suspension Bridge was closely related to the struggle to defend the independence of the Republic of Indonesia.
After the events of the Dutch Military Aggression 11 (December 19, 1948), the Bantar Suspension Bridge was controlled by Dutch troops and was used as a military post for the Dutch army since December 27, 1948.
Colonel Bambang Sugeng as Commander of Division III MBKD (Djawa Command Headquarters) in the western part of Central Java and Yogyakarta at that time formed several Wehrkreise (Resistance Areas). The Yogyakarta area was under the command of Wehrkreise III troops led by Lieutenant Colonel Suharto. Furthermore, Lieutenant Colonel Suharto divided his command area into several Sub-Wehrkreise. One of the Sub-Wehrkreise troops formed was Sub-Wehrkreise 106 in Kulon Progo with commander Lieutenant Colonel Soedarto. These troops are TNI troops which were originally formed as part of the implementation of Operation Strategy Number 1, namely the "Scorched Earth Strategy" (to carry out sabotage/destroying public facilities to hinder enemy mobilization). The mission of the Sub-Wehrkreise 106 Kulon Progo troops was to attack this military post while simultaneously damaging/destroying the Bantar Suspension Bridge.
During the General Offensive on March 1, 1949, Sub-Wehrkreise Troop 106 Kuion Progo succeeded in suppressing and holding back the Dutch troops at the Bantar Suspension Bridge post. This condition resulted in the Dutch troops being unable to move to provide assistance to the Dutch troops who were being attacked by Wehrkreise Ill troops in the city of Yogyakarta. The event that the Dutch troops were detained at the Bantar Suspension Bridge in the battle had a major impact on the success of the March 1 General Offensive in the City of Yogyakarta.
As a marker of the importance of the Bantar Suspension Bridge for the struggle to defend the Sovereignty of the Republic of Indonesia, on March 1, 1995 the General Chairperson of the Yogyakarta Wehrkreise (Resistance Area) III Association, General TNI (Purn) Soesilo Soedarman inaugurated the Bantar Lama Bridge (Bantar Suspension Bridge), as "Struggle Monument"
B. CONSTRUCTION
The Bantar Suspension Bridge is a steel frame suspension bridge 176 m long and 6 m wide which is supported by two double towers (pylons) that rest on double pillars 13 m high from the normal surface of the river. The construction of the Bantar Suspension Bridge was the first suspension bridge built in the Dutch East Indies at that time. As a type of suspension bridge, the Bantar Suspension Bridge implements a bridge system in which the entire framework of the bridge is suspended from a main steel cable (wire rope) with an intermediary steel cable hanger. The bridge's main cable rests on two double towers, and the two towers rest on double pillars to transmit the loads received by the bridge and then forward them to the foundation. This bridge is also equipped with a quarter circle disc which is supported by joint and roll construction which functions as the main cable support at the ends of the bridge. Furthermore, the end of the main cable goes into the ground with an anchor equipped as a ballast. This serves to continue the load and vibration received by the bridge. The type of bridge floor is in the form of wooden planks on steel girders, and on top of the bridge plank floors are given a layer of asphalt concrete as a surface course.
The bridge is divided into three parts, namely the 80 m long central span which is supported by double towers and rests on double pillars and the 48 m long side spans which are supported by abutments. Above the double pillars there is a 10.8 m high tower as the seat of the main steel cable (wire rope). The Bantar Suspension Bridge is also equipped with a ±30 cm thick fence. The main cables which are the main construction on the bridge are 3 on both sides, with a diameter of 1.5 inches (3.81 cm) for each cable. To lock the ends of the steel cables, quarter-circle discs are used to continue the cables into the anchorage construction. In the past, to increase the ability to withstand the load capacity of the bridge, 3 main cables of the same shape and diameter were added so that on both sides of the bridge there were 6 main cables. The additional 3 hanging cables lock with additional quarter-circle discs behind each of the four previously existing discs. The four additional discs function together to continue steel cables into the anchorage construction.***