Structural and civil engineers have warned that parking heavy duty vehicles such as articulated box and cylinder trucks (trailers) for days at a stretch, as seen in Apapa, Lagos, has an adverse impact on the integrity and structural stability of those bridges, with the risk of failure or total collapse if such activity is not checked.
The experts add that given the history of parking heavy duty vehicles for prolonged periods on them, the bridges in Apapa need to be tested periodically, so as to avert sudden failure.
In the past few years, Apapa, Nigeria’s premier port city, has been under siege, with virtually every route to the city, including bridges, being overrun by trucks of all sizes, making living and commuting in and around that city a nightmare.
Apapa, which is home to Nigeria’s two busiest seaports, from where both the federal and Lagos state governments generate huge monthly revenue, is degenerating into a wasteland, in which residents and businesses are marooned with decaying and collapsing roads and bridges.
Bridges are constructed for rolling and not stationary loads; they are generally designed for certain maximum dynamic loads of fast moving vehicles, distributed evenly over their surface, which is why the engineers are saying that the scenario in Apapa poses a grave danger to the bridges as well as human to lives and properties within the vicinity of the bridges.
Gabriel Ojo, a civil engineer at Sanni, Ojo & Partners Consulting Limited, argues that it is most unlikely that the bridges structure and integrity will be adversely affected from the point of view of overload from the ‘empty’ trucks, but many of those trucks are not in perfect condition.
“Because many of them are not in perfect condition”, he explained in an email response to a question, “many of them are likely to have oils, including petrol, diesel, engine oil, brake oil etc, dripping on the bridges; these oils are organic solvents that naturally dissolve the asphalt topping and cause the bridges topping and the decks to deteriorate very fast”.
He further said, “some of these oils also get washed down the joints and may attack the elastomeric or other rubberised materials of the joints and will certainly reduce the service life of the bridges.
“It is these oils that are far more troublesome and worrisome than the overload; the oils certainly have great adverse impact on the integrity of the bridge and road structure”.
Femi Akintunde, a structural engineer and GMD/CEO, AMFacilities, affirms, stressing however that heavy duty trucks parked at close proximity to one another and in static condition over a long period of time have adverse impact on the bridges. “What this implies is that the combined weight of the vehicles parked in this condition will be far more than what the bridge was designed to carry under normal condition.
“The implication of this situation is that the higher concentration of the static load of these closely parked trucks on the bridge will subject its structures to high degrees of stress at the various joints and support joints than normal, leading to faster wear and tear at critical points, which ultimately puts the structural integrity of the bridges at great risk of collapse or catastrophic failure”, he said.
Most of the bridges that criss-cross Lagos landscape were constructed many years ago, with little or no maintenance. Babatunde Fashola, the minister for power, works and housing, noted during an inspection of repair work on Apapa-Ijora bridge, that the bridge, which was constructed 40 years ago, has not received any form of maintenance despite its terrible condition.
Akintunde warned that unless there is regular maintenance inspection to detect early signs of deterioration and failure, and necessary preventive measures taken, the situation on Apapa bridges poses grave danger to lives and properties of public users.
“Government should take urgent action to decongest the bridges, in order to avert any disaster that may follow this mindless parking of heavy duty vehicles on bridges”, he advised, calling for improved provision of roads and bridge infrastructure around Apapa, which has seen increased volume of traffic plying that axis. “The situation as it is today, has potential negative economic and public safety impact”, he added.
The traffic situation in and around Apapa is worsening with each passing day and in the last two weeks, it has taken an embarrassing dimension, prompting the Lagos State government to ban further entry of trucks into the city until the current situation is addressed.
Lagos residents, especially those whose businesses, offices, schools, residences are in that part of town, are in high expectation that government lives up to its responsibility and brings back sanity to Apapa, the proverbial hen that lays golden egg for both the state and the federal government.
CHUKA UROKO
