Extant Panel Zone Design Procedures for Steel Frames Are Questioned

1999 ◽  
Vol 15 (2) ◽  
pp. 361-369 ◽  
Author(s):  
Robert E. Englekirk
Keyword(s):  
Steel Frames ◽  
Code Design ◽  
Moment Frames ◽  
Design Procedures ◽  
Panel Zone ◽  
Special Moment Frames ◽  
Current Design ◽  
Current Code ◽  
Observed Behavior

Current design procedures for steel special moment frames (SMF) promote panel zone yielding. Reliance on this yielding is likely to result in poor frame performance in spite of the fact that it has been demonstrated that panel zones can yield. Eight previously tested subassemblies are analyzed for compliance with current code design procedures. The observed behavior of these subassemblies is discussed and contrasted to behavior objectives of steel SMF's. Revised design procedures are proposed.

Cast Modular Panel Zone Node for Steel Special Moment Frames. I: Analytical Development

2007 ◽  
Vol 133 (10) ◽  
pp. 1393-1403 ◽  
Author(s):  
Robert B. Fleischman ◽  
Xuejun Li ◽  
Yong Pan ◽  
Ali Sumer
Keyword(s):  
Moment Frames ◽  
Panel Zone ◽  
Special Moment Frames ◽  
Analytical Development

Analytical Methodology to Predict the Beam Overstrength Considering the Composite Slab Effects

2018 ◽  
Vol 763 ◽  
pp. 826-834
Author(s):  
Tushar Chaudhari ◽  
Gregory A. MacRae ◽  
Des Bull ◽  
George Charles Clifton ◽  
Stephen Hicks
Keyword(s):  
Steel Frames ◽  
Lateral Force ◽  
Moment Frames ◽  
Steel Moment Frames ◽  
Design Strength ◽  
Analytical Methodology ◽  
Panel Zone ◽  
Proposed Model ◽  
The World ◽  
Moment Resisting

The design strength of moment resisting steel frames in seismic regions around the world is generally calculated without considering strength enhancement caused by the slab. For column and panel zone design in New Zealand, the beam overstrength including the slab effect is considered. If the slab could be detailed to provide reliable lateral force resistance, then considering it directly in design would result in smaller beam sizes and more economical steel frames. In this paper, a simple analytical model (considering all key modes of failures) to predict the variation in strength due to the presence of the slab is proposed and validated with the experimental data. The proposed model to develop dependable slab contributions may change the design of steel moment frames around the world.

The influence of currents on circular secondary clarifier performance and design

1996 ◽  
Vol 34 (3-4) ◽  
pp. 405-412 ◽  
Author(s):  
Andrea Deininger ◽  
Frank W. Günthert ◽  
Peter A. Wilderer
Keyword(s):  
Wastewater Treatment ◽  
Density Currents ◽  
Clear Water ◽  
Performance Measurements ◽  
Design Procedures ◽  
Secondary Clarifier ◽  
Current Design ◽  
Hydraulic Load ◽  
Novel Design ◽  
Wastewater Treatment Systems

Density currents in the deeper zones of clarifiers and currents in the clear water zone have a significant influence on clarifier performance. Measurements of flow velocity profiles were conducted in full-scale horizontally flown circular secondary clarifiers. Relations between the hydraulic load and the development of density currents could be detected. Those patterns are not taken into account in current design procedures. Stationary design approaches are mainly based on the overflow rate. Novel design methods based on the dynamic behavior of flow and density distribution in clarifiers are needed in order to improve the efficacy of wastewater treatment systems.

scholarly journals Fragility assessment of existing low-rise steel moment-resisting frames with masonry infills under mainshock-aftershock earthquake sequences

2021 ◽  
Vol 19 (6) ◽  
pp. 2483-2504
Author(s):  
Luigi Di Sarno ◽  
Jing-Ren Wu
Keyword(s):  
Seismic Vulnerability ◽  
Steel Frames ◽  
Steel Frame ◽  
Second Phase ◽  
Moment Frames ◽  
Damage Level ◽  
Masonry Infills ◽  
Aftershock Sequences ◽  
The Impact ◽  
Multiple Earthquakes

AbstractThis paper presents the fragility assessment of non-seismically designed steel moment frames with masonry infills. The assessment considered the effects of multiple earthquakes on the damage accumulation of steel frames, which is an essential part of modern performance-based earthquake engineering. Effects of aftershocks are particularly important when examining damaged buildings and making post-quake decisions, such as tagging and retrofit strategy. The procedure proposed in the present work includes two phase assessment, which is based on incremental dynamic analyses of two refined numerical models of the case-study steel frame, i.e. with and without masonry infills, and utilises mainshock-aftershock sequences of natural earthquake records. The first phase focuses on the undamaged structure subjected to single and multiple earthquakes; the effects of masonry infills on the seismic vulnerability of the steel frame were also considered. In the second phase, aftershock fragility curves were derived to investigate the seismic vulnerability of infilled steel frames with post-mainshock damage caused by mainshocks. Comparative analyses were conducted among the mainshock-damaged structures considering three post-mainshock damage levels, including no damage. The impact of aftershocks was then discussed for each mainshock-damage level in terms of the breakpoint that marks the onset of exceeding post-mainshock damage level, as well as the probability of exceeding of superior damage level due to more significant aftershocks. The evaluation of the efficiency of commonly used intensity measures of aftershocks was also carried out as part of the second phase of assessment.

Proposal methodology to assess debris current design in traditional Chilean Bridges

2019 ◽  
Author(s):  
Matías A. Valenzuela ◽  
Francisco Hernandez ◽  
Nicolás A. Valenzuela ◽  
Flavio H. Álvarez ◽  
Hernan Pinto
Keyword(s):  
Code Design ◽  
Hydraulic Analysis ◽  
The Real ◽  
Newtonian Flows ◽  
Concrete Girders ◽  
The North ◽  
Current Design ◽  
Rain Fall ◽  
Collapse Behavior ◽  
Desert Zone

<p>During the last five years, the north of Chile was impacted by several natural disasters not considered in the traditional code design. During 2015 a great rain fall occurred in a desert zone, it is not prepared by this amount of water, producing soil and debris currents from the mountain to the sea (about 100 km).</p><p>These phenomena produced an important damage in the infrastructure, specially focused on roads and bridges. The main damage detected was the collapse of the infrastructure (piers and abutment) and the unlinking between deck and piers.</p><p>This paper presents a proposal methodology to assess the effect of these currents on bridges, using the case of study of the Chañaral Bridge, a multi-supported bridge, with four concrete girders, slab girder and two spans of 20 meters supported in two abutments and one concrete pier, over the Charañal River.</p><p>A sensitive hydraulic analysis via FEM was carried out using non-Newtonian flows (high density) representing the real final topography-condition of the current. A FEM of the bridge was carried out too considering a Non- Linear transient load. The inputs for model are the outputs from the hydraulic model in order to define the condition that produce the same collapse behavior showed after the real debris current.</p><p>Finally, results of this methodology are discussed, providing a comprehensive methodology, step by step, in order to obtained similar results according to the 2015 event.</p>

Seismic performance of composite RCS special moment frames

2013 ◽  
Vol 17 (2) ◽  
pp. 450-457 ◽  
Author(s):  
Bahman Farahmand Azar ◽  
Hosein Ghaffarzadeh ◽  
Nima Talebian
Keyword(s):  
Seismic Performance ◽  
Moment Frames ◽  
Special Moment Frames
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