The Oyo State Chapter of the Nigerian Institution of Highway & Transportation Engineers (NIHTE), a Division of the Nigerian Society of Engineers under the Chairmanship of Engr Esther Oluwakemi Oladeji visited the construction works on Oyo-Ogbomoso Federal road on Tuesday, 17th June, 2021.
The Federal Controller of Works, Engr Ibrahim Kayode is the ER of the project. Engr Olusola Olarerin, the Chief Engineer was prompt to receive members at km 43
She explained that the project is a link section (section 2) of Ibadan – Ilorin road and covers a length of 52Km stretching from Km 43 – Km 95. She introduced members to Engr Niyi Olowoyeye, representing Reynolds Construction Company (RCC) the Contractors handling the project.
Engr Niyi Olowoyeye accompanied by Mr. John Jimoh, the company Safety Officer conducted members to various strategic locations on the project. The road is entirely on a new profile alignment.
According to a statement made available to newsmen: “All the hydraulic structures mainly Pipe and Box culverts are 95% completed. Major parts of the cutting areas on earthworks are under water. Consequently, the volume of unsuitable materials on earthworks was enormous. These have to be removed and replaced by suitable lateritic materials hauled from borrow pit. Coupled with this exercise is the laying of 150mm plastic pipes, unevenly perforated, surrounded by granite filters and rapped with geotextile materials as weep pipes to drain off underground water that may otherwise constitute serious failure to road pavement. This idea is to ensure the drain pipes are constantly receiving clean water and permanently impervious to silt.
“The pavement width on sub grade formation is 20cm lateritic sub-base, 20cm stone base, twin binder of 6cm each and 4cm wearing course. The central median is closed in urban area and opened on rural alignment. The open median width is 6.6m each from the inner side of pavement on either road direction.
“There are five major structures consisting of 4 flyovers on water location and 1 bridge on water locations over Oba River. The structures on dry locations are essentially to control traffic volume as grade separated interchanges with minimum of 5.4m headroom. One of these flyovers is designed with 4 clover leaves at each of its entry and exit locations. These concrete structures are of circular piers with abutments loaded with 0.5m x 1.6m depth prestressed post tension concrete beams. The contractor was magnanimous to oblige us with a company crane to lift members to the top deck of one of the flyovers to view reinforcement arrangements on a deck ready for insitu concrete cast. The particular flyover has a length of 50 meters in 2 spans of 25m. The beams were already loaded with 11cm thick reinforced precast concrete slabs on which the reinforcements were arranged while 11cm concrete is to be cast insitu. This brings the total deck thickness to 22cm.
“Essentially, the importance of quality control on road project cannot be overemphasized. Members visited the contractor’s material laboratory where all materials are regularly tested, ascertained and controlled. The laboratory contains Asphalt Compactor Factor Machine, Extractor to determine bitumen content and Oven Dryer. Others are Bitumen Stability Tester, Vacuum Machine, Bitumen Penetration Machine, Concrete Crushing Machine and Hot Plate.
“The project as at the time of visit is 50% completed and with scheduled funding, it is expected to be fully completed in June 2023.”
