Revised ASCE-41 modeling recommendations for moment-resisting frame systems

Nonlinear static and dynamic analysis is utilized by engineers to evaluate the seismic behavior of new and existing structures in the context of performance-based earthquake engineering. Numerous experiments on steel moment-resisting frames and their components have been conducted over the past two decades. The findings from these tests suggest that the current ASCE-41-13 nonlinear component models do not adequately simulate the steel MRF component behavior. As part of the ATC-114 project, new modeling recommendations are proposed for several structural steel components of new and existing MRFs including, steel beams, columns, the beam-to-column web panel zone, column bases and column splices. These recommendations are based on a consistent methodology that takes advantage of unique experimental data as well as insights from detailed finite element analyses. For each structural component of interest a set of equations is developed to predict their first-cycle envelope and monotonic backbone curves that can be directly used in nonlinear frame analysis. The proposed equations also include information related to the associated modeling uncertainty of each of the input model parameters. Through an array of illustrative examples, it is shown that the new recommendations reflect much more accurately the behavior of structural steel components from the onset of damage through the loss of their load carrying capacity

ATC-114 Next-Generation Hysteretic Relationships for Performance-based Modeling and Analysis

Nonlinear analysis has become an increasingly useful and important tool for evaluation, upgrade and design of structures for seismic resistance. However, despite steady improvements in analysis capability, most practice remains anchored to guidelines developed more than 20 years ago. Under its ATC- 114 project, the Applied Technology Council is developing updated hysteretic envelope models for use in seismic analysis of new and existing buildings. The intent of this project is to support the development of updated building code criteria contained in such standards as ASCE 7 and ASCE 41. Project support is provided by the National Institute of Standards and Technology

Post-transcriptional regulation of androgen receptor mRNA by an ErbB3 binding protein 1 in prostate cancer

Androgen receptor (AR)-mediated pathways play a critical role in the development and progression of prostate cancer. However, little is known about the regulation of AR mRNA stability and translation, two central processes that control AR expression. The ErbB3 binding protein 1 (EBP1), an AR corepressor, negatively regulates crosstalk between ErbB3 ligand heregulin (HRG)-triggered signaling and the AR axis, affecting biological properties of prostate cancer cells. EBP1 protein expression is also decreased in clinical prostate cancer. We previously demonstrated that EBP1 overexpression results in decreased AR protein levels by affecting AR promoter activity. However, EBP1 has recently been demonstrated to be an RNA binding protein. We therefore examined the ability of EBP1 to regulate AR post-transcriptionally. Here we show that EBP1 promoted AR mRNA decay through physical interaction with a conserved UC-rich motif within the 3′-UTR of AR. The ability of EBP1 to accelerate AR mRNA decay was further enhanced by HRG treatment. EBP1 also bound to a CAG-formed stem-loop in the 5′ coding region of AR mRNA and was able to inhibit AR translation. Thus, decreases of EBP1 in prostate cancer could be important for the post-transcriptional up-regulation of AR contributing to aberrant AR expression and disease progression

Magna Carta, the Rule of Law and the Limits on Government

This paper surveys the legal tradition that links Magna Carta with the modern concepts of the rule of law and the limits on government. It documents that the original understanding of the rule of law included substantive commitments to individual freedom and limited government. Then, it attempts at explaining how and why such commitments were lost to a formalist interpretation of the rule of law from 1848 to 1939. The paper concludes by arguing how a revival of the substantive commitments of the rule of law is central in a project of reshaping modern states

A cyclic backbone curve for squat reinforced concrete shear walls

by Siamak Epackachi, Nikhil Sharma, Andrew Whitaker, Ronald O. Hamburger and Ayse Hortacs

A cyclic backbone curve for shear-critical reinforced concrete walls

Backbone curves are used in seismic design standards as the basis for developing component models for nonlinear static and dynamic analysis. Herein, data from 240 tests of rectangular, barbell, and flanged shear-critical walls are assembled and analyzed to develop an improved cyclic backbone curve for use in nonlinear response-history analysis. Values of drift ratio and normalized lateral force at the control points on the cyclic backbone curve are identified. The effects of design parameters, including wall aspect ratio, axial load, day-of-test concrete compressive strength, vertical and horizontal web reinforcement ratio, reinforcement ratio in the boundary elements, and yield strength of reinforcement, on the coordinates of the control points are addressed. The accuracy of equations for peak shear strength is assessed using the collected test data.by Siamak Epackachi, Nikhil Sharma, Andrew Whittaker, Ronald O. Hamburger and Ayse Hortacs