Jesus E. Moron Irausquin
Prof. Emeritus, The University of Zulia
Next August 24 we will be celebrating the first sixty years of the inauguration of the “General Rafael Urdaneta Bridge” (PGRU), an engineering work that for the first time materialized the direct land connection between Maracaibo, the capital of Zulia state, with the rest of the Venezuelan territory. Although, the project of this work was identified from the beginning with the name of “Bridge over Lake Maracaibo”, it was built crossing the strait that makes the natural connection between the body of marine water Gulf of Venezuela and the body continental water Lake Maracaibo.
The work inaugurated on August 24, 1962, was really made up of two physical components. One, the concrete bridge of 8,670 meters in length, considered an engineering work of great importance for the time, both for the characteristics of its architectural and structural design, as well as for the resources and materials that were used in its construction; the second was the section of Highway No. 1, between the western head of the bridge and the link distributor with the Maracaibo – Perijá road corridor.
Destiny as a geodetic engineering student at the University of Zulia (LUZ) for when these majestic works were being built, gave us the opportunity to work on their final phase, under the leadership of Ing. Gustavo Lepage, professor of the Roads Department. of Communication of the Faculty of Engineering, practicing the inspection measurements associated with the execution of the works of the first section of the highway, such as: the installations of the toll plaza of the western head of the bridge (Punta de Piedras end) ; the pontoons for the attention to the pluvial drainage in the crossings of the road embankment with the natural trace of the Peru ravine; and the installation of the cyclone fence demarcating the limits of the road protection strip.
An event that marked us during the execution of these works was the unforeseen trip with the oil pipeline coming from the La Concepción field, whose production was stored in the Punta de Piedras pancake yard for later export. This oil infrastructure was located just north of the western head of the bridge under construction. The aforementioned pipeline was traced between the La Concepción field and Punta de Piedras, following a rectilinear direction for its greatest length; part of its original surveillance road is now popularly known as the Palito Blanco road. In addition, it was assumed as the territorial limit between the municipalities of Maracaibo and San Francisco.
The Punta de Piedras headwaters was enabled to install the fundamental work camps for the execution of the work. In the northern sector, adjacent to the tank farm, the construction consortium enabled the three logistics spaces required for this type of engineering work, such as: 1) the buildings for their work offices; 2) temporary residences for professional and technical personnel from abroad; and 3) the area enabled with the primary monuments (leveling and triangulation) for geodetic and topographic measurements, as well as the facilities required for the calibration and verification of the high-precision instruments that were used in the measurements throughout the execution of the project. the work. In the southern sector, the facilities were set up for the official dependencies of the Ministry of Public Works (MOP), responsible for the inspection of the execution of the work, and those conditioned for logistical support. These facilities and related spaces, once the work was completed, were reconditioned for its functional administration.
The area and facilities that were conditioned for the calibration of the measurement instruments were assigned to the School of Geodetic Engineering (EIG) of the Faculty of Engineering of LUZ as a field laboratory, under the coordination of Ing. Heinz Henneberg, who later having coordinated and led the entire process of high-precision measurements that the construction of the bridge required, he joined the university as a teaching and research staff.
With the entry of Prof. Henneberg, the EIG became the custodian of the geodetic data that was collected, validated and processed during the construction of the bridge. Likewise, the prototypes of the instruments that were used to guarantee the precision and accuracy of the different structural components of the work, characterized by the technological quality that was available for the applied geodetic control by the mid-twentieth century, were incorporated into our school. in large-scale engineering works. This is how the EIG-LUZ Measurement Department still preserves the following instruments that were used during the construction of the PGRU and its main sections of road access:
- For angular measurements: Wild T3 Theodolite; Kern DKM3 theodolite;
For elevation measurement: Ni3 level; INVAR vertical sights;
For distance measurements: 50 m INVAR material tapes, INVAR horizontal stay and Tellurometer microwave equipment;
For verification of distance measuring equipment: Prototype pair of the Universal Standard Meter, with a calibration certificate issued by the International Office of Weights and Measures based in Paris, France.
From the moment the bridge began its road communication activity, the University of Zulia, through the EIG, was present in the observance, surveillance and quantification of the behavior of its structure, an activity that remained continuous for several years. years under the coordination of Prof. Henneberg himself. With these initial precision geodetic measurements, a progressive evaluation program of the settlement of the structure was consolidated, considering the effects of the weight of its components, the influence of the moving loads of vehicular traffic to which it was subjected, and the natural reactions of balance of the subsoil strata before the driving of the support piles of that great reinforced concrete structure.
The activity of the groups led by Prof. Henneberg generated geodetic data on the behavior of the bridge since its inception of operation, and also allowed the location of the first concrete structures that had begun to be affected by corrosion of their structures to be detected. reinforcing steel, caused by the action of chlorides present in the body of water, due to the traditional discharge of wastewater generated by the population settled on the banks of the strait where the bridge was built.
In order to face the reconstruction of the collapsed section due to the impact of the Esso Maracaibo tanker, which occurred on April 6, 1964, when the bridge was just about to complete its first 20 months of operation, the EIG-LUZ had the precise basic information with the location of the structural components that were affected, which made it easy to quickly quantify the magnitude of the damage that was caused to Pile 31 and the collapsed section. As a result of this unexpected event and the emergency with which its repair was attended, the participation of the Faculty of Engineering of LUZ was expanded in the investigation of the structural behavior of the bridge, deepening in the observation of the progressive corrosive effect that was perceived in the piers closest to the Punta de Piedras and Punta Iguana extremes, reaching a report in 1976, the observance of significant corrosive effects in one of the guy wires of the section of the bridge that crosses over the navigation channel. Some time later, in 1979, one of the tensioning cables of Pile 22 broke, an event that led to the replacement of the entire original system of cables for the section, which was completed the following year.
In these first six decades of operations, the Rafael Urdaneta Bridge has been subject to a changing administration. In 1962, once authorized for its operation by the MOP, the Ministry of Transport and Communications (MTC) assumes the controls for its operation, maintenance and conservation; This activity of central administration was maintained until 1984, when, after achieving the first advances in the process of decentralization of the Venezuelan public administration, the management, care and administration of its majestic bridge was transferred to the Zulia state government. for which the General Rafael Urdaneta Bridge Autonomous Service was created.
As of this date, LUZ, through the Center for Corrosion Studies of the Faculty of Engineering, increased its research on the bridge, reaching an agreement with the aforementioned Autonomous Service, thus facilitating the participation of a team of up to 30 university researchers. (among them, EIG professors Heinz Henneberg and Antonio Gonzalez). This group of researchers, in each of their specialties, developed a variety of studies that, finally, led to the presentation of the Rehabilitation and Major Maintenance Program of the “General Rafael Urdaneta Bridge”, which included protocols to follow for the repair and rehabilitation of the structural components affected, both by corrosion and by the natural wear and tear caused by heavy vehicular traffic. Between 1995 and 2005, the Zulia state government allocated budgetary resources that made it easier to meet some minor needs, such as, among others: repainting, tensioning and changes of guy lines in the central section, cleaning and reconditioning of supports and mobile supports for table beams, tests to combat battery corrosion, monitoring and control of the transport of heavy vehicles. Likewise, the punctual measurement of meteorological parameters and tests for the quantification of movements of the structure applying modern GPS satellite positioning techniques were included.
The behavior and care that the bridge has had, which is now celebrating sixty years of functionality, is not a surprise for the LUZ university students. Other Morandi-type or model bridges, which were built in other latitudes of the planet almost at the same time as ours, have already indicated to us which is the care route to follow for those who are still standing.
Today, Zulian university students call on the regional and national leadership to promote an already very mandatory approval of ordinary and extraordinary financial resources to develop the corresponding annual programs of preventive and corrective maintenance, as well as the conservation and recovery of the most important concrete road infrastructures of Venezuela, such as: the General Rafael Urdaneta Bridge in the state of Zulia and the Angostura and Orinoquia bridges, between the states of Bolívar and Anzoátegui.
We hope that by the time our General Rafael Urdaneta Bridge is inaugurated in the next five years, we can celebrate it very Zulian style.