Performance-based specifications (PBS) may increase concrete quality and sustainability by facilitating innovations in material selection and proportioning. This is particularly relevant now with increased interest in a broader set of minimally processed minerals for use as supplementary cementitious materials (SCMs) or fillers; these are often industrial and agricultural byproducts and with limited performance history in concrete. This study compares traditional largely prescriptive concrete design, following practices currently allowed by the Georgia Department of Transportation, with three new concrete designs which do not comply with current specifications but offer increased sustainability. Three metrics are assessed for each mixture: the associated cradle-to-gate CO₂ emissions, a metric that incorporates the environmental burden of concrete, compressive strength at 28 days, and surface resistivity measurements taken weekly from 28 to 56 days. A framework is proposed to statistically analyze compressive strength data to pre-qualify mix designs, which can be broadly applied to reduce time-consuming iterative testing and to help meet sustainable development goals. The aim is to foster innovation in material use and mixture design towards an increased durability and performance, while reducing environmental impact and minimizing risk.

Fibre reinforced concrete (FRC) is becoming widely utilized in segmental linings due to the improved mechanical performance, robustness and durability of the segments. Further, significant cost savings can be achieved in segment production and by reduced repair rates during temporary loading conditions. The replacement of traditional rebar cages with fibres further allows changing a crack control governed design to a purely structural design with more freedom in detailing. Macro synthetic fibres (MSF) are non-corrosive and thus ideal for segmental linings in critical environments. Although fibre reinforcement for segments is relatively new, recent publications such as the ITAtech “Guidance for precast FRC segments – Volume 1: Design aspects” or the British PAS 8810 “Tunnel design – Design of concrete segmental tunnel linings – Code of practice” have now given more credibility to this reinforcement type and the basis for design. This paper presents and discusses the design methodology for precast tunnel segments and in particular the tasks associated with the use of MSF reinforcement. Temporary loadings as well as long term load behaviour will be addressed. A case history from the Santoña–Laredo General Interceptor Collector, currently under construction in northern Spain, will illustrate the specific benefits of MSF reinforcement for segmental linings.

With over 80 years of history, it is only in the last 20 years that the use of fiber reinforced polymer (FRP) materials has become feasible for bridge applications in part due to the ever increasing requirement to make structures last longer, with the current American Association of State Highway Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) Bridge Design Specifications requiring that structures be designed for a 75 year design life; but also in the development of cost effective production techniques, and the introduction of FRP materials, which bring the cost and strength of FRP materials closer to traditional steel reinforcement. Published documents provide comprehensive recommendations on design methodology, predictive equations, and recommendations for strength and service limits states. In this paper, the background of FRP-prestressed concrete bridges is discussed and trial bridges are designed. Research needs to advance the state of the art are identified and delineated.

Performance based seismic design (PBSD) has created new opportunities for enhanced performance, improved cost efficiencies, and increased reliability of tall buildings. More specifically, flexibility with initial design methods and the utilization of response history results for design, not just verification, have emerged. This paper explores four refined design methods made available by the employment PBSD to influence seismic performance and identify areas of importance. First is the initial proportioning of reinforcement to encourage plastic hinge behavior at specific locations. Second is the initial proportioning of wall thicknesses and reinforcements to encourage a capacity-based design approach for force-controlled actions. Third is the mapping of observed strain demands in shear walls to specific detailing types such as ordinary and special boundary zones. Fourth is an efficient envelope method for the design of foundations. Through these design methods, initial proportioning can be conducted in a more refined way and targeted detailing can result in cost savings. A case study of a recently designed high-rise residential building demonstrates that cost savings can be achieved with these methods.

A 160-foot (≈ 49 m) tall 12–story reinforced concrete special moment frame building is designed following ASCE 7-16 and ACI 318-14, and assessed using three Performance-Based Seismic Engineering (PBSE) standards and guidelines including ASCE/SEI 41, the Tall Buildings Initiative (TBI) guidelines for performance-based design of tall buildings, and the Los Angeles Tall Buildings Structural Design Council (LATBSDC) procedures. The assessments are performed at the combination of two performance and hazard levels including Collapse Prevention (CP) at the risk-targeted maximum considered earthquake (MCER) hazard level and Immediate Occupancy (IO) at a frequent ground motion level with 50 percent probability of exceedance in 30 years, i.e. serviceability performance level. Based on the recommendations of each of the three PBSE documents, nonlinear finite element models are implemented in OpenSees. Through nonlinear time-history response analyses, the finite element models are subjected to eleven ground motions that are selected following the ground motion selection recommendations in ASCE 7-16. Assessment results indicate that for the serviceability performance level, the code-compliant building meets the design requirements of the three PBSE documents for the inter-story drift ratio and inelastic deformation of the structural components. At the MCER hazard level, although the building essentially satisfies the design requirements for the peak inter-story drift ratios and inelastic deformation, the mean of the residual inter-story drift ratios as well as the envelope of the residual drift ratios do not meet the limits of the TBI and LATBSDC guidelines. The results indicate that the newly designed building meets the ASCE 41 acceptance criteria but does not meet the design requirements set in TBI and LATBSDC guidelines.