PurposeMany road authorities considered contracting out road maintenance to the private sector based on performance measures as an alternative and better solution than traditional methods of contracting. It highlights issues of interest to road authorities in the context of saving maintenance costs and managing contracting times effectively. This method is named as performance based maintenance by contracting (PBMC) and has substantial success records in minimizing infrastructure maintenance costs in many developed and developing countries over the last two decades. It has received the attention of researchers and practitioners. However, the literature on PBMC is reasonably high although the concept of PBMC is relatively new. The purpose of this paper is to carry out a comprehensive state of the art review of the literature that has been conducted in the recent years.Design/methodology/approachA total of 62 published report and journal articles related to performance based maintenance by contracting for road network system has been analysed and reviewed in this paper.FindingsThis paper analyses the literature on PBMC and presents examples of developed and developing countries that have been successfully maintaining their road network systems using PBMC as their preferred method of contracting.Practical implicationsThe potential of reducing maintenance costs, increasing the quality of works and reducing the chance of corruption in the long run in developing countries are the challenging issues for PBMC, which needs more attention. This paper can be used as a base or platform for future research in the area of PBMC such as developing optimal policies and cost models.Originality/valueThis paper would be useful for the research on PBMC. It would be beneficial for the engineers or professionals in improving the performance of road maintenance and management.

This paper presents the challenges for effectiveness and sustainability of flood risk management strategies and technologies by critically reviewing flood management practices. The study reveals that reliable flood prediction is limited by the characterisation of floods that have multiple causes and hydrological uncertainties due to variability in climate and river morphology. Moreover, changing land use in floodplains and the potential of creating new risks limit the risk assessment and evaluation process of flood control projects. Hence, sustainability analysis mechanisms, including 'dynamic sustainability' concepts, should be adopted in the flood management planning process. Investigations into the proportional contribution of structural and non-structural measures to reduce total flood risk could assist in better decision making. Gaining improved understandings of the perception on flood risk and safety, and risk communication methods, for present and future stakeholders is crucial. Extensive research on the above challenges would reveal pathways for developing sustainable flood risk management strategies.

Road authorities always strive to reduce the maintenance costs of road infrastructure systems using various traditional methods of contract. Contracting out road maintenance to the private sector based on performance measures is an alternative solution to maintain road infrastructure in a cost-effective way and is named as Performance Based Maintenance Contracting (PBMC). Many countries have succeeded in minimizing road infrastructure maintenance costs using performance-based maintenance contracts over the last two decades. However, implementation of PBMC is still a challenge for many developing countries because of resource and skill limitations, corruption and poor management systems. This paper discusses and analyses the problems and difficulties in the successful implementation of PBMC in developing countries.

A full-size test program was carried out on 26 simply-supported and continuous reinforced and partially prestressed concrete beams to study the cracking behaviour and damping characteristics of concrete beams. The beams were subjected to free vibration tests and logarithmic decrement values corresponding to each load level were measured. Separate regression analyses on the reinforced and the partially prestressed beams were undertaken. These analyses resulted in two separate empirical formulae for predicting the logarithmic decrement of damping in reinforced and in partially prestressed beams. Comparison with test results from all 26 beams indicates that the predictions are accurate. It is also found that the damping formula for reinforced beams is applicable to both single and continuous spans. The proposed damping formulae predict damping from the residual crack widths of the beams. As such, formulae developed for predicting residual crack widths from given variables defining the beams and their deflection-span ratios are also reported.

The falling weight deflectometer (FWD) is a non-destructive testing device that has been used by many road agencies worldwide since 1980 for structural evaluation of flexible pavements. In early 2000, the world first Doppler laser-based traffic speed deflectometer (TSD) was developed by Greenwood Engineering, and now eight TSD vehicles are in use worldwide. The two main advantages of the TSD technology are: (a) the ability to carry out continuous bearing capacity measurements instead of discrete points, (b) that testing can be carried out at traffic speeds without the need for lane closures with a stationary device such as FWD. The objective of this paper was to study the structural performance of flexible pavements using TSD deflection data. The study successfully established a correlation between maximum deflections TSD-D 0 and FWD-D 0 that are derived from the two devices. This study also drew some interesting conclusions in that deflection data collected by TSD could be transformed to FWD equivalent structural numbers with simple models as derived in the study. The outcome of this study was an established methodology for reporting structural performance at network level utilizing TSD deflection data.