Pengaruh Klasifikasi Kelas Situs Menurut SNI 1726-2019 Terhadap Keruntuhan Progresif pada Struktur Gedung Tidak Beraturan

Seiring perkembangan teknologi konstruksi gedung, pembangunan gedung bertingkat dengan struktur tidak beraturan semakin bertambah demi memenuhi aspek estetika gedung maupun akibat keterbatasan lahan. Bentuk struktur tidak beraturan ini berpengaruh terhadap keruntuhan progresif gedung. Selain aspek desain, pada perencanaan gedung beban gempa harus direncanakan dengan peraturan baru yang berlaku yaitu SNI 1726-2019. Salah satu perubahan yang terjadi pada SNI 1726-2019 adalah klasifikasi kelas situs. Penelitian ini bertujuan untuk mengkaji pengaruh klasifikasi kelas situs terhadap keruntuhan progresif struktur gedung tidak beraturan. Penelitian ini dilakukan dengan menganalisis elemen struktur berupa kolom dan balok sebelum dan sesudah menghilangkan salah satu kolom struktur berpedoman pada General Services Administration (GSA) dengan beban gempa yang bekerja beban gempa statik ekivalen pada keempat klasifikasi kelas situs yaitu SB (Batuan), SC (Tanah keras), SD (Tanah sedang) dan SE (Tanah lunak). Pemeriksaan kekuatan struktur menggunakan perangkat lunak berbasis elemen hingga untuk mengetahui nilai Demand Capacity Ratio (DCR), Bending Moment Ratio (BMR) dan Robustness Indicator (R). Struktur dikatakan mengalami keruntuhan progresif apabila nilai DCR > 1,5. Dari hasil analisis diketahui nilai DCR dari kelas situs SB ke kelas situs SE mengalami kenaikan sedangkan nilai BMR mengalami penurunan. Hasil analisis juga menunjukkan bahwa keruntuhan progresif tidak terjadi pada keempat kasus kegagalan kolom dan perbedaan kelas situs terhadap gaya aksial dan momen, namun terjadi terhadap gaya geser. Nilai Robustness Indicator (R) yang didapat mendekati sama dengan satu (R≈1), nilai tersebut mengindikasikan bahwa penyaluran beban berjalan dengan normal.

Designs for Politics in Intellectual History

While working on a report on federal office space in 1962, Daniel Patrick Moynihan, then a young assistant secretary at the Department of Labor, began writing what would become the Guiding Principles for Federal Architecture and shaped the direction of the federal government's architecture for decades. The principles outlined two requirements for a federal building: “First, it must provide efficient and economical facilities for the use of Government agencies. Second, it must provide visual testimony to the dignity, enterprise, vigor, and stability of the American Government.” Achieving those requirements demanded a willingness to follow architects’ ideas, an avoidance of “an official style,” and—if needed—paying “some additional cost to avoid excessive uniformity in design of Federal buildings.” Citing Pericles, Moynihan argued that this pursuit would provide clear visual evidence the American government “do[es] not imitate—for we are a model to others.” Over the years these principles and the subsequent Design Excellence program under the General Services Administration commissioned designs by an eclectic range of architects for federal building projects.

Structural integrity of precast concrete modular construction

The American Concrete Institute’s (ACI’s) Building Code Requirements for Structural Concrete (ACI 318-19) and Commentary (ACI 318R-19) contains structural integrity provisions for precast concrete panel buildings but does not address the structural integrity of precast concrete modules. ACI 318 requires spaced steel ties in all directions to tie the precast concrete panel elements together. These criteria are impractical for precast concrete modules due to the construction methods and the overall rigidity of each module. Precast concrete modules are inherently stable, even when subjected to General Services Administration criteria for partial removal of structural walls or corners, which require that if a portion of a wall or an entire module is removed, the remaining portions must have sufficient capacity to carry the resulting gravity loads. This paper examines the stress increases due to partial wall removal and the possibility of total module removal. It discusses strength reserves, provides recommendations for future editions of ACI 318 and the PCI Design Handbook: Precast and Prestressed Concrete, and presents conceptual connections that provide the continuity and ductility needed to maintain structural integrity following total module removal.

Verificação de colapso progressivo em vigas de concreto armado

Este trabalho tem como objetivo utilizar o Método dos Caminhos Alternativos de Cargas (MCAC) e os critérios estabelecidos pelo General Services Administration (GSA), a fim de verificar, em um estudo de caso, se as vigas de uma estrutura de concreto armado, dimensionada conforme a NBR 6118 (ABNT, 2014), resistem ao colapso progressivo. Após a análise, as vigas, que possivelmente sofreriam danos, foram redimensionadas para resistir ao colapso. Os resultados indicaram que as vigas têm uma grande probabilidade de sofrer colapso progressivo, apenas com relação aos momentos fletores. Para combater o colapso, observou-se um aumento significativo na área de aço das vigas.

By the Numbers: DAP: Digital Analytics Program

Every day, millions of people access government websites. Over the thirty days preceding the date this article was written, the National Weather Service and the National Library of Medicine each received more than 50 million visits. According to the US General Services Administration, there are over 1,300 dot-gov domains in use by federal agencies. Given the immense resources involved in building and maintaining these websites, sound decisions about allocating these resources are important. And that means decision makers need good data.