Evaluation of Story Drift under Pushover Analysis in Reinforced Concrete Moment Frames

The accurate prediction of story drift and its distribution along the height of the structure is very critical for seismic performance evaluation since the non-structural damage is directly related to the story drift. Pushover analysis is an accepted method for seismic evaluation of existing structures as well as performance-based design of new structures. Regarding assumptions and limitations in pushover analysis, there is a need to estimate the error that would affect the accuracy of story drift. This paper investigates the validity of pushover analysis to predict story drift under different lateral load patterns. For this purpose, several reinforced concrete moment frames with different heights were analyzed using pushover and nonlinear time history analyses and obtained results were compared to evaluate the error level

Evaluation of an Interview-Based Internship Class in the Construction Management Curriculum: A Case Study of the University of Nebraska-Lincoln

Internships have been shown to be impactful tools to connect students’ learning in academia with real-world industrial needs. To help the students to get more out of their internship experience, some universities provide a summer internship class in which students do class assignments based on their experiences during their internship. There have been numerous studies on the benefits of internships. However, the benefits of a potential internship class for students in construction management (CM) programs at universities have not yet been investigated. This paper demonstrates the structure of an interview-based internship class and investigates its effectiveness. We have focused on the CM program at the University of Nebraska-Lincoln (UNL) as a case study. We sent online questionnaires to the intern students who took the class, students’ mentors, and the professors who taught the class. The results indicate that despite some challenges to meet the requirements of the class, the students, their mentors, and the professor found the class beneficial. The results of this paper are expected to help CM programs with the establishment and improvement of internship classes in their curriculum

Material quantities and estimated construction costs for new elevated IRC 2015-compliant single-family home foundations

Residential foundation selection is critical for the lifetime performance of the project, but the type of foundation selected can depend on cost. This study aims to compare the new construction costs of residential slab-on-fill and four types of crawl space foundations for residential projects by quantifying the material quantities for each and exploring the effect of building characteristics on material quantities and total costs. The building characteristics selected are size (139 m2, 186 m2, and 232 m2), footprint aspect ratio (1:1, 1:2.5, and 1:5) and first floor elevation (0 m–1.2 m in 0.3 m increments). We find that material quantities and total costs change not only with building size and elevation, but also with footprint aspect ratio. Applying 2022 RSMeans Building Construction Cost data, the results show that for any building size, aspect ratio, or elevation, raised wood flooring on pier foundations ($118–$180 per m2) and slab on fill ($103–$211 per m2) are the least expensive, while crawl space foundations with stemwalls are the most expensive ($147–$280 per m2). The results of this study can be used by residential builders, developers and designers in evaluating foundation costs and design alternatives. The methodology may also be adapted for use in other applications such as flood mitigation or energy efficiency projects or environmental sustainability assessments

Improved building-specific flood risk assessment and implications of depth-damage function selection

Average annual loss (AAL) is traditionally used as the basis of assessing flood risk and evaluating risk mitigation measures. This research presents an improved implementation to estimate building-specific AAL, with the flood hazard of a building represented by the Gumbel extreme value distribution. AAL is then calculated by integrating the area under the overall loss-exceedance probability curve using trapezoidal Riemann sums. This implementation is compared with existing AAL estimations from flood risk assessment. A sensitivity analysis is conducted to examine the variability in AAL results based on depth-damage function (DDF) choice. To demonstrate the methodology, a one-story single-family residence is selected to assess the financial benefits of freeboard (i.e., increasing lowest floor elevations). Results show that 1 ft. of freeboard results in annual flood risk reduction of over $1,000, while 4 ft of freeboard results in annual flood risk reduction of nearly$2,000. The sensitivity result suggests that the DDF selection is critical, as a large proportion of flood loss is counted below the top of the first floor. The findings of this paper will enhance DDF selection, improve flood loss estimates, encourage homeowners and communities to invest in flood mitigation, and provide government decision-makers with improved information when considering building code changes

Freeboard life-cycle benefit-cost analysis of a rental single-family residence for landlord, tenant, and insurer

Flood risk to single-family rental housing remains poorly understood, leaving a large and increasing population underinformed to protect themselves, including regarding insurance. This research introduces a life-cycle benefit-cost analysis for the landlord, tenant, and insurer [i.e., (U.S.) National Flood Insurance Program (NFIP)] to optimize freeboard [i.e., additional first-floor height above the base flood elevation (BFE)] selection for a rental single-family home. Flood insurance premium; apportioned flood risk among the landlord, tenant, and NFIP by insurance coverage and deductible; rental loss; moving and displacement costs; freeboard construction cost; and rent increase upon freeboard implementation are considered in estimating net benefit (NB) by freeboard. For a 2,500 square-foot case study home in Metairie, Louisiana, a two-foot freeboard optimizes the combined savings for landlord and tenant, with joint life-cycle NB of $23,658 and$14,978, for a 3% and 7% real discount rate, respectively. Any freeboard up to 2.5 feet benefits the tenant and NFIP, while the landlord benefits for freeboards up to 4.0 feet. Collectively, results suggest that at the time of construction, even minimal freeboard provides substantial savings for the landlord, tenant, and NFIP. The research provides actionable information, supporting the decision-making process for landlords, tenants, and others, thereby enhancing investment and occupation decisions

Generalized Cost-Effectiveness of Residential Wind Mitigation Strategies for Wood-Frame, Single Family House in the USA

Wind is one of the deadliest and most expensive hazards in the United States. Wind hazards cause significant damage to buildings and economic losses to homeowners. Economic losses average approximately $3.8 billion annually from hurricane winds and are not decreasing, even despite enhanced construction practices to reduce wind damage. Thus, the effectiveness of mitigation strategies should be evaluated in order to lower the cost incurred by this hazard. Several studies have suggested building code improvements to mitigate the wind hazard, this additional comprehensive research provides selecting economically beneficial mitigation strategies to consider in building code revisions. In a step toward addressing this need, the current study was conducted to determine the cost effectiveness of mitigation strategies for new and retrofit construction of a wood-framed, single-family, residential building case study. Net benefit, defined as the difference between the life-cycle wind loss before and after implementation of the mitigation strategy, was calculated for 15 wind mitigation strategies and their combinations, with new and retrofit construction costs ranging between$1,200 to $12,000 and a decision-making time horizon ranging between 5 and 30 years. Payback periods, defined as the number of years to recover the investment, were calculated for each mitigation strategy. Results were summarized by cost effectiveness for all ASCE 7 wind speed contour intervals. The results of this study serve as a starting point for further refinement of the economic justification needed to properly evaluate potential building code changes

Predictive Statistical Cost Estimation Model for Existing Single Family Home Elevation Projects

One of the most preferred flood mitigation techniques for existing homes is raising the elevation of the lowest floor above the base flood elevation (BFE). Determination of project effectiveness through benefit-cost analysis (BCA) relies on the expected avoided flood loss and the project cost. Conventional construction cost estimates are highly detailed, considering specific details of the project; however, mitigation project decisions must often be made while considering only highly generalized building details. To provide a robust, generalized project cost estimation method, this paper implements data modeling and mining methods such as multiple regression, random forest, generalized additive model (GAM), and model evaluation and selection with cross-validation methods to hindcast elevation costs for existing single-family homes based on average floor area, increase in floor elevation, number of stories, and foundation type. Project cost data for homes elevated in Louisiana, United States, between 2005 and 2015 are used in cost prediction analysis. The statistical modeling results are compared with detailed estimations for several types of home foundations over a range of elevations. The results show substantial agreement between regression predictions and detailed estimates using RSMeans cost data

Evaluation of an Interview-Based Internship Class in the Construction Management Curriculum: A Case Study of the University of Nebraska-Lincoln

Internships have been shown to be impactful tools to connect students’ learning in academia with real-world industrial needs. To help the students to get more out of their internship experience, some universities provide a summer internship class in which students do class assignments based on their experiences during their internship. There have been numerous studies on the benefits of internships. However, the benefits of a potential internship class for students in construction management (CM) programs at universities have not yet been investigated. This paper demonstrates the structure of an interview-based internship class and investigates its effectiveness. We have focused on the CM program at the University of Nebraska-Lincoln (UNL) as a case study. We sent online questionnaires to the intern students who took the class, students’ mentors, and the professors who taught the class. The results indicate that despite some challenges to meet the requirements of the class, the students, their mentors, and the professor found the class beneficial. The results of this paper are expected to help CM programs with the establishment and improvement of internship classes in their curriculum