Questions tagged [civil-engineering]
Questions that fall into the problem domain of civil engineering or one of its sub-disciplines. Questions about buildings or other structures could usually use the "structural-engineering" tag also.
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why are horizontal and vertical stresses on an element in soil mass considered as principal stresses?
Despite the fact that there are shear stresses also involved while considering deformations in soil why are the horizontal and vertical stresses on an element as shown in below figure considered as ...
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Bolt tensile load through an "intermediary"?
Following up on this question, does it change anything if the bolted arm is an intermediate arm (e.g. some sort of mating interface like below)? That is, the arm receiving the load is connected to the ...
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The heaviest road-legal truck
The question is what is the heaviest road-legal truck?
I exclude road trains (except for one full trailer in addition to regular load) and special payloads (such as wind turbines, very large ...
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Concrete block VS Red brick for Kitchen extension
Is the wall composition/layers the same if I were to choose either Concrete block or Red brick?
Which has a higher strength?
Which is generally more preferred for extensions?
Note please, this is for ...
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How can depth of flow in a supercritical flow get affected when the flow passes through a constriction of width less than the critical width?
When a supercritical flow approaches a constriction having a width less than the critical width does the depth of supercritical flow decrease upstream so as to increase specific energy? If it does ...
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What are these objects attached to the cables of this bridge?
Recently, I noticed some strange objects attached to the cables of a bridge (in Münster, Germany):
What are they called and what is their purpose? They don't look like connectors of any kind nor do ...
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Searching for geometric modeller to investigate behaviour of beam when deflected
I have the scenario where I wish to model the movement of a simply supported beam under a central point load. I've done some stuff in R Studio to come up with deflection plots and that's fine. In ...
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Laying problem in designing axis points in static design?
First of all, there is a simple pattern plan on the halter. Here, we design an axis point passing through the midpoints of the columns and use it in the static calculation program. However, when we do ...
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A question on understanding the nature of static equilibrium
In the statics lesson, we do not think about the effects of forces on objects. In other words, we do not assume that an object can break, bend or twist. In the same situation, we can combine different ...
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Are the compressive and tensile stresses in the beams always equal?
If we examine the $example-1$ of cantilever beam 1 above, there will be shear force $Ft$ and moment $M$ that will keep the beam in balance statically. However, when we examine the strength, that is, ...
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What is collapse multiplier in OptumG2 software? How to reduce the error percentage for calculating active Earth pressure?
I am working on an analysis of a retaining wall. After doing a limit analysis on the structure, the collapse multiplier that I am getting for both upper and lower limit is very high. As it is not ...
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Fixed End Moment for a point load at edge span
Usually, i solved this kind problems by divide into 3 span, AB, BC, CD
Then, using Fixed End Moment and Cross Methode to find the Moment
But, i cant find Fixed End Moment for the point load at the ...
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Can I modify the roof trusses in my barn to raise the roof
We're trying to raise the roof on our 1.5 storey pole barn. We're intending on just replacing half the roof as shown below. each truss is supported by 4x6 columns (the long side of the 4x6 is bolted ...
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Thermal Expansion and Stress in a Heated Beam
Consider the case of a beam that is supported in such a way that expansion can occur freely. Suppose that the beam is heated in such a way that the temperature varies with the depth of the beam. Let $...
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Interaction Diagrams - Reinforce Concrete Design
I am confused on how to located the c value of an interaction diagram. I am given a unsymmetrical bar placement and there is a result that produces a negative moment meaning the location of the point ...
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Deflection of hanging beam in two parts
Can anyone quickly explain the analytical method for finding the deflection at the base of a beam shaped like this? Note the top beam is a truncated cone and the bottom is a uniform cylinder.
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Typical Runoff velocity values
I am computing runoff velocities for rainfall falling over an area using St-Venant 1D momentum equation. I wanted to have some idea if my computed velocities are within a reasonable range of what one ...
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Fluid Mechanics about Hydrostatic Pressure
The rectangular gate will open authomatically, when the depth of water becomes
very large. What is the minimum value of d that will cause the gate to just open?
The width of the gate is 2 m.
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How to correctly use the thermal conductivity coefficient formula?
I'm trying to help a friend.
We are trying to use the formula below to calculate the thermal conductivity coefficient of a composite material (styro-bamboo).
Q=100 Watts, d (or thickness)= 20mm, A= ...
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Why does an increased thickness in saturated zone reduce the impacts of groundwater mounding for the Hantush Method?
NJDEP requires that the impacts of groundwater mounding on proposed infiltration basins be analyzed as a condition of approvals.
The prescribed method for conducting this analysis is using the Hantush ...
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Why forces on bottom curved cylinder surface equal to the weight of water and weight of imaginary water?
So basically in a video I was taught that, for a submerged cylinder the forces acting on the bottom curved surface is equal to the weight of water directly above + imaginary water weight, if someone ...
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What does it mean for something to be 'in shear'?
When I was first introduced to 'shear stress' it was using the concept of a beam, this beam was under tension and we determined a value for shear stress for different planes on the beam. As we expect ...
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What is the equivalent rotational/angular stiffness of a beam
I'm trying to model a larger system and working through a conceptual issue. I'm familiar with the concept of expressing the stiffness of a beam as an equivalent spring stiffness like in the image ...
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Sizing a groundwater storage well for stormwater runoff; using the area below a patio as a recharge pit
I would like to build a patio of 900 square feet. My city engineer says that:
"any increase in impervious coverage over 500 square feet must recharge 3-inches of runoff for each square foot of ...
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When acceleration spectra is inside period band?
I can't seem to grasp on how a acceleration response spectra (and it's correspondent signal) is inside the period band of a design spectra. I have my period band from Mode 1 to the mode correspondint ...
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Inverse analysis of one Storey structure
The displacement history of one story structure is known due to an unknown ground motion. The dynamic properties, such as mass and lateral stiffness, are known, and dimensions were also given. How to ...
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Can bars made out of PET be used to reinforce concrete?
I watched a video, in which a man shows how to make something that looks like a rebar out of PET bottle strips.
This made me wonder: can something like this be used to reinforce concrete when ...
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Autocad Change Properties for All Object
Does anyone know how to change the Vertex X and Vertex Y value for all of the dots? Because some of the red dots has a different vertex X and Y value which also causes the shape to be slightly ...
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where should center of gravity of cargo for the entire structure to be JUST stable?
My work: My answer for 1 is 2.5m (floats)
For 2:
MG must be positive and Ym - Yg must be positive
I am not sure where to go from here.
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Difference between elastic and inleastic response spectra?
As far as I know inelastic response spectra is supposed to consider the geometric distribution, in plan and height and also the importance, nonetheless this concept is a little vague and I could not ...
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Are air exchange rates (AER or air change rates) under estimates or over estimates?
Doing a problem set where I need to deduce the air exchange rate of a building, and ran into this conceptual question. My gut instinct is to think that AERs are overestimates because the measures that ...
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Repurpose part of a rice farm for a farm house
I'm considering repurposing a part of a rice farm into a farm house. I've seen this done elsewhere and after about 10 years, the entire floor just sank. (I saw in 10 years, didn't know the situation ...
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Finding the bending moment diagram for an indeterminate continuous beam
In a recent lecture, we had the following example of an indeterminate continuous beam where we must find the redundant support reaction at $A$:
This was found by removing the support at $A$, and then ...
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Dlubal Rfem Seismic Analysis
I’m learning Dlubal Rfem recently and I have a problem about seismic analysis. When Equivalent Lateral Load is bigger than Modal base shear;for example on Sap2000 we scale modal base shear and we make ...
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Thermal performance
Which is higher thermal performance: R15 effective wall calculated per ASHRAE90.1-16 or an R15 effective wall calculated per the Thermal Bridging Guidelines?
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After how many days can concrete framework be removed?
After how many days can concrete framework be removed? Do admixture chemicals like superplasticizer or accelerating admixtures allow early removal of concrete framework?
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How to create a Six Bar Linkage with the Stephenson Topology
I wanted to clarify a point in Mechanical Engineering. To create a six-bar linkage with the Stephenson Topology, do I just have to pick 5 joint locations and connect them with binary links? Then I ...
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Hertzian contact between sphere and plane in 2D
Can anyone tell me if these formulas (for the radius of the contact area etc.) of a contact problem between a sphere and a plane are also valid for 2D problems:
https://en.wikipedia.org/wiki/...
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Hydraulics sluice gates and hydraulic jumps
I was wondering if anyone has an understanding on hydraulic jumps and sluice gates?
Why can you only use the energy equation for before and after the sluice gate? Why not at two points after the ...
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What is the difference between goods yard, goods station and marshalling yard?
In railway engineering what is the difference between goods yard, goods station and marshalling yard?
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"Slender" Column in bridge design
I am currently designing a cable-stayed bridge and my design gave me a 45x50cm column. But now that I see my column's unsupported height is 7m. I checked for slenderness and it is of 93. Now, ...
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Thickness and Diameter of hollowed Galvanised Steel pole/tube required to sustain 80kg passive weight aswell as suddenly absorb of 60-80kg body weight
Here is a diagram of the designed frame.
Label A) points to the 4 horizontal bars underneath the transparent brown sheet (the ground)
Label B) shows the ovals (surface level) on all other bits of ...
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What use are those glass panels?
I often come across glass panels that are attached to the edge of the ceilings of public interior areas.
What purpose do they serve?
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How to derive the below expression for resisting length of a hill road?
The image above shows the longitudinal profile of a hill road. In order to fix the alignment of the hill road the concept of resisting length is used. How to obtain the expression as shown above for ...
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Is floating gradient for a road only relevant to descending parts of the road?
Does floating gradient of a road only pertain to the descending part of the road or is it also defined for ascending parts?
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What is wrong with the derivation for x coordinate of Centroid of quarter of a circle below?
In the derivation for x coordinate of centroid of a quarter circle as shown in the image below why is the sign coming out to be negative when actually it should be positive?
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Why is the frustum of a cone used to slump test of concrete and not a cylindrical tube?
While performing the slump test for knowing the workability of a concrete mix one uses a tube having the shape of frustum of a cone in order to conduct the test. Why is not a cylindrical tube used ...
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How does a variable speed moving walkway work?
How can a travelator (i.e. a moving walkway) such as those used in airports be mechanically made to increase speed incrementally when travelling towards the middle and to decrease speed incrementally ...
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What is the most accurate mathematical model of a cantilever beam's bending?
I read there are multiple models for it,
Plate theory, euler-bernoulli, timoshenko beam theory etc
Which is the most accurate for modelling the bending of a stressed cantilever beam?
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49
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Understanding forces acting on solids
I've just started learning about axial stresses on solids, primarily soil samples and this is the first time I've encountered proper forces on solids, and we consider this over an area, previously I ...
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