Engineer says steel bar quality essential in high rises
The quality and integrity of steel bars used in high-rise buildings cannot be overstated, an engineering expert said, expressing alarm over efforts to downplay the need to emboss the grade of steel in reinforced bars to identify those that are quench-tempered and those of better quality micro-alloy.
Emilio Morales, former chair of the Association of Structural Engineers of the Philippines, said there should be serious effort to ensure that better quality steel rebars are used in the country especially in high-rise construction.
Morales made the appeal when he appeared at a recent Senate hearing of the committee on trade, commerce and entrepreneurship, chaired by Sen. Koko Pimentel, where he stressed the importance of the quality and integrity of steel bars used in high-rise buildings.
Of particular concern for Morales, a professor and top lecturer in engineering schools, was a reported statement made by Roberto Cola, vice president of Steel Asia and also president of the Philippine Iron and Steel Institute, that there was no need to emboss the grade of steel on steel rebars since the much used quench-- tempered (QT) or thermo-mechanical treatment (TMT) for manufacturing supposedly “upgrades the steel.”
“That is a criminal offense, because there will be a catastrophic failure of strength in multi-story and high-rise buildings when a major earthquake occurs,” Morales said.
Morales has been lobbying for transparency in the production of steel bars, and has discussed the dangers of using QT bars in a paper he published entitled “The Clear and Present Danger – the Use of QT or TMT Rebars in Seismic Zone 4.”
Morales said that quenching is the process of subjecting the hot steel bars to rapid cooling. This creates an outer layer that passes the tests conducted by the Bureau of Product Standards of the Department of Trade and Industry. However, tests done by the BPS do not expose the danger that could arise from these quenched steel bars, which should not be welded, bended, threaded and galvanized.
The engineer has also emphasized that studies in Italy, Australia and New Zealand have concluded that quench tempered steel bars are not for high-rise buildings, and that these have been banned in other countries such as Canada, Taiwan and Japan.
The Senate hearings are being conducted by the committee on trade, commerce and entrepreneurship, in aid of legislation, particularly for proposed Senate Resolution 802 filed by Sen. JV Ejercito, which intends to craft “legislation and policies that may help revitalize the steel industry in the country,” while Senate Resolution 412 by Sen. Panfilo Lacson, has an “end view of protecting public safety, through the enactment of remedial measures that will stop the proliferation of substandard steel bars in the country.”