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Questions tagged [deflection]

87 questions
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How should a bridge deck closure pour be positioned?

The Question: Where should a closure pour be located relative to centerline of girder and how should the closure pour width be detailed/designed? And now, a little background: When designing a steel girder bridge using phased construction with dead…
CableStay
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What is the effect of end diaphragms on prestressed girder forces/deflections?

I'm encasing the abutment ends of prestressed concrete bridge girders in concrete before the deck pour. (For lateral stability and to prevent the soil from spilling through.) Discussion of intermediate diaphragms for prestressed girders abounds, but…
CableStay
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Can the thickness of a guard post be derived purely from energy principles?

Consider an ordinary staircase with a banister rail supported by a wall at one end and a steel post of constant profile at the other end. The base of the post is embedded rigidly in the fabric of whatever structure the stairs are part of. The post…
Stilez
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How is shelf deflection determined?

Question: How is shelf deflection determined? More specifically, how is the deflection determined when one or more edges of the plate have reinforcing edging applied to them? I have been able to find plate deflection equations in a number of…
user16
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Deflection of thin plate with 1 free edge and deflection > thickness

I have an thin uniform rectangular steel plate supported on 3 sides and free on one, and supporting a uniform load. I'm trying to determine what thickness of plate I need to keep deflection below a given value, but the deflection may not be "small"…
Stilez
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Deriving the deflection force equation for a beam that is fixed on both ends

I want to calculate the force-displacement equation for a beam that is fixed at both ends. I think I should use the superposition principle but I am not very sure how to get started. I know that for, say, a beam with one fixed-end and applied load…
user5785
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Round beam deflection under its own weight

I'm trying to calculate how much simply-supported round beams of several materials and diameters deflect under their own weight plus an additional weight in the middle. I know the material densities so I can calculate weight of the entire beam, and…
suprjami
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Undesired vibration of a beam under foot traffic

The other day I was in the waiting room of a doctor's office in a new building as part of UCLA medical complex. A new construction as part of multi million dollar extension of existing medical complex in west Los Angeles. I felt a small tremor…
kamran
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Should long-term prestressed girder camber always be upward?

When considering long-term prestressed girder camber (for a bridge), what are the implications (if any) of long-term downward deflection on girder performance? Should prestressing be designed to ensure that long term camber is always upward? I'm…
CableStay
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What plastic material is best for a snap-fit design?

I'm designing a plastic holder that will secure a metal part with snaps. Which plastic will be able to take multiple removals and re-insertions without getting weaker (bent out of shape) over time? [EDIT 1] The following is my progression as I…
Davbog
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How to calculate filament deflection and force applied to teeth by toothbrush bristles?

I am trying to get my head around the behaviour and the effectivity of the the filaments movement of a toothbrush inside your mouth. I want to know the mechanical formulas and/or properties that I need to consider in order to understand how the…
Kevin Mamaqi
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Maximum deflection of a beam with both ends fixed and distributed load

I'm designing a part, and I'm trying to figure out what distance a slot should be from the bottom of the part. For simplicity in analysis, I'm approximating the region between the bottom of the slot and the bottom of the part as a beam that is…
fp.monkey
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How much deflection can/should I accept with Aluminum Extrusions?

I plan building things with aluminum extrusions. On this website I can calculate the deflection depending on the profile length and load. https://8020.net/deflection-calculator I.e. if I select a 20/20 (mm) profile with 500mm length and 150kg…
Edgar
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What is the load response of a threaded fastener?

Due to the fact that pipe flanges rely on bolts, and bolts rely on friction, it seems obvious to me that in deflecting to meet the load, the nut will immeasurably turn. So my question is - how much? In other words, given a time based varying load…
Mark
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Why do we increase the minimum beam/slab depth if we increase the grade of the reinforcement to control the deflection

I've just started to study reinforced concrete design and I came across this in the "Design of Concrete Structures" by Dr.Nilson. and I was wondering why do we increase the minimum thickness if we are using stell grade more than 60 ksi instead of…
user22341
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