PLUS monitors, inspects highway slopes consistently

KUALA LUMPUR (Oct 11): Ever get the feeling that the slope may come down on you as you drive along the highway? Never fear.

PLUS Malaysia Berhad (PLUS) monitors and inspects the 6,820 slopes along its highways consistently to ensure the safety and comfort of highway users, more so during the wet monsoon season.

Its chief operating officer, Zakaria Ahmad Zabidi, said PLUS has classified the slopes according to the level of risk so as to facilitate monitoring and inspection.

“The classification of these slopes will enable us to give attention to, monitor as well as carry out maintenance of high-risk slopes. In general, these slopes are divided into Low Risk (Category C), Medium Risk (Category B), High Risk (Category A) and Very High Risk (Category AA),” he told Bernama.

He said that since 2004, PLUS has identified five risky slope monitoring zones, namely Bukit Merah, Jelapang, Gua Tempurung, Bukit Lanjan and Maokil. The zoning is based on the level of the slope risk and the off-border watershed area, he added.

Zakaria said there has been no annual increase in the slope areas but if there is a change in the number of slopes due to the construction of new interchanges, this will be recorded in the slope inventory through the Expressway Slope Management System (EsMas).

He said periodic inspections and visual monitoring were also carried out according to the categories, every four months in the case of Category AA slopes; every six months for Category A slopes; every 12 months for Category B slopes and every 18 months for Category C slopes, while a general inspection of high-risk slopes is done every two months.

The monitoring is carried out using several methods, including from the air using a helicopter for the high-risk slopes and in the five monitoring zones, he said.

“At the same time, we also use the rainfall gauge with the Real-Time Monitoring System (RTMS). This system was developed to facilitate PLUS in managing the highway asset maintenance system through the transmission of real-time information or data to the related units, departments or individuals for further action,” he said.

More importantly, he said, the RTMS system is able to indicate an imminent slope collapse (when a slope collapses abruptly due to the weakened self-retain ability of the earth) in relation to rainfall, where the system will issue a warning if the intensity of rainfall exceeds the threshold.

Another technology used by PLUS is the Total Expressway Maintenance Management System (TEMAN) which acts as a centralised database for asset management of its highways.

Zakaria said the TEMAN system keeps a detailed record of the technical data and risk assessment scale up to the outcome and the maintenance records.

“The company also uses the PLUS Geospatial, an application using geospatial technology to assist pre-monitoring or preliminary studies which are also used as support data for slope monitoring activities,” he said.

According to him, since 2014, PLUS has spent RM75 million for works on maintenance and upgrading of slopes along its highway network.

Up to 160 PLUS engineers and technical teams are involved specifically in carrying out the inspection, assessment and maintenance of slopes at its highways, namely the North-South Expressway (with 5,695 slopes), ELITE Expressway (389 slopes), Linkedua (376 slopes), Seremban-Port Dickson Highway (193 slopes) and others such as the Butterworth-Kulim Expressway (BKE) and the Penang Bridge (167 slopes).

Zakaria also said that the company is regularly collaborating with the Malaysian Remote Sensing Agency and Universiti Putra Malaysia (UPM) to undertake research related to slopes, such as on landslides and underground waterways.

He said one of the main objectives of the research is to locate the possibility of landslides and their impact on the PLUS highways based on the relevant parameters.

“The results of this research give an overview of the conditions of the slopes along the highway and the off-border watershed areas, in the slope monitoring zones, as the collected data enables us to concentrate on the right areas,” he said.