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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28 views

Assessment of steel beam for lifting to Eurocode 3

A client wishes to use an existing steel beam to lift a 1 tonne load using a sling. The 3 m long beam is measured as UB 203x133 visually observed at both ends to be secure with end-plates with all ...
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1answer
34 views

Plate thickness for repair of completely corroded web

The web of a H-section column has been completely corroded at the air-moisture interface with the concrete encasement leaving a hole in the web. The proposal is to break out the existing concrete and ...
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24 views

Need help identifying this three-layer diverging diamond-style interchange

I'm an avid fan of Cities: Skylines, and it has occurred to me that one of the types of interchanges that seems to fare very well with the simulated traffic is this three-layer diverging diamond (...
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1answer
33 views

Cause of stepped crack up and away from lintel

What are the likely causes of a stepped crack up and away from the edge of a lintel? See the diagram below.
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2answers
123 views
+100

Can a speedbump safeguard a pipeline located below?

Recently I noticed a concrete speed bumper created near my parking. On enquiring the purpose, the committee who took the decision told me that the purpose of the bumper is to safeguard an existing ...
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3answers
52 views

Design Roller Compacted Concrete Pavement Section

I have been asked to consider using RCC instead of traditional PCC on an upcoming project. For a rough order of magnitude estimate, can I assume that the pavement section design will be similar? I ...
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1answer
32 views

Capacity of plain concrete foundation on grade [Civil UK]

A client has asked whether a container can be placed on an existing unreinforced concrete foundation of depth 100 mm. The grade of the concrete is unknown. How can the capacity (in kPa) of this plane ...
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14 views

Minimum nominal cross section for a masonry column that supports only a roof for a structure in Seismic Design Cat B?

Minimum nominal cross section for a masonry column that supports only a roof for a structure in Seismic Design Cat B? Trying to find this referenced in IBC and no luck.
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21 views

Optimization of ash stockpile height to minimize haul truck fuel costs

How would I find out the optimum height of an ash stockpile in order to minimize diesel haulage costs, for a CAT haul truck? My stockpile height is required to be between 25m to 50m. I have worked ...
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0answers
24 views

Difference between ACI Code and Eurocode in Stiffness modifiers?

According to the ACI Code stiffness modifiers (modifiers used to reduce the moment of inertia) are used for each structural elements for example 0.7 for columns and 0.35 for beams... For those who ...
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0answers
17 views

Seismic Design Changes between ASCE and UBC Code?

what is the difference between the seismic design between ASCE and UBC code? from load combinations to loads applied to the history between the sudden shift or change in the code. and which one of the ...
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1answer
24 views

What is the Difference between ASCE and IBC Code?

What is the fundamental difference between the ASCE Code and IBC Code and what is the objective of each one? Thank you in Advance.
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1answer
22 views

Slab Stiffness Modifiers applied in Vertical Elements design but not in Slab design?

Why in the design of vertical elements (columns and walls) for a structure against lateral loads (such as seismic and wind) we use a slab (or shell) with a stiffness modifiers (such as 0.25 according ...
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1answer
24 views

Drop Panel Design Above Columns?

How to design a drop panel at a column in case the column above is rotated or not aligned to the below column (see image below), the code that i am using is the ACI Code if any reference for the ...
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1answer
30 views

At what level is the Grade Beam most effective at pile cap level or at Slab-on-grade level?

The primary two functions of a Grade/Tie Beam in spread footing and/or pile caps foundation system is to support the Slab-On-Grade (S.O.G) and/or to take the moment from eccentric footing (or moment ...
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20 views

Difference between Allowable Bearing capacity Service and Ultimate?

When we calculate the dimension of a foundation we always use the allowable SERVICE bearing capacity (lets call it qs) and all the necessary checks are based on this value qs. My question is why does ...
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1answer
30 views

Is there a relationship between depth/diameter/etc… of meteoric craters and the strength (eg:compressive strength) of the target material (sand…)?

So I am trying to write a high school research paper (3700 words) on the topic above. I am not sure if there is such a relationship, but I think intuitively we can agree that different materials will ...
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26 views

Problem regarding mathematical operators in concern with impulse

So, my Question is why do we have $$\begin{align} -S &= m_H (V_H' - V_H) \\ -S \cdot l &= \theta_B (w_B'-w_B) \end{align}$$ because with what I understood about impulse so far, it should ...
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1answer
54 views

Why is the thread of the screw linear? Can it be wavy?

I noticed that the screw-on of my water tap often loosens itself up after I rotate the tap left and right enough times. Every time I rotate the tap left, it loosens the screw a bit, then if I rotate ...
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3answers
73 views

How to get corrugated plastic roofing strips to span 3m for rainwater exclusion experiment without building additional ground supports?

I'm trying to build structures to exclude some percentage of rainwater on experimental plots. I have three 20ft beam supports across the plot, spaced 3m apart and held in place by 4x4 posts that were ...
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1answer
46 views

Dimensions of a bar when it is subjected to axial pull

Determine the change in dimensions of a rectangular bar of length 2 m, width 200 mm, and thickness 100 mm, when it is subjected to an axial pull of 20 kN in the direction of its ...
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2answers
57 views

What is difference between lift and elevator and hoist?

I am very confused by the three terms:lift and elevator and hoist Are they all technically same thing or different??
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0answers
20 views

What is the effect of ageing on preconsolidation pressure?

Preconsolidation pressure is the maximum effective vertical overburden stress that a particular soil sample has sustained in the past. How far in the past does the soil remember its loading/the ...
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2answers
125 views

Can a crisscrossed metallic skeleton resist earthquakes for buildings?

To follow up with my previous question on the seismic design of buildings, I would like to ask if it makes sense to support buildings with strong thick 'crisscrossed' metallic frames. I have the ...
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1answer
41 views

3 x 1 stone under footing and sump crock

I am having a house built and the builder found organic soils during the excavation. They removed the soils and then filled the cavity with 1x3 stone (see picture). This is the corner where the sump ...
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1answer
44 views

Do you need to be a chartered engineer to submit structural calculations to building control in the UK?

I’m a graduate structural engineer with 4 years experience, working in the UK. A family friend is planning on doing a house extension which will require some structural calculations for steel beams. ...
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1answer
86 views

Looking to design a cantilever support to hold up an 80kg projector

I need to make a support (preferably metal) for a projector to be fixed on the wall. The projector size is: Width: 0.7m Length: 1.1m Weight: 80kg If anyone knows how i can solve this please let me ...
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2answers
67 views

Can a horizontal foundation safeguard against earthquakes?

I have not taken any course in civil engineering. What I was taught was that a broad base would prevent something from toppling. So it makes me wondering instead of nailing the foundation of a ...
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1answer
97 views

Is it OK for a 2 story house not have a column or pillar

sorry for my english. I was looking to buy a house. I saw some in my hometown, which is very affordable. but on a picture of the house they are selling I found on the net troubled me. no pillar/column,...
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2answers
58 views

Identifying Compression and Tension as well as Hogging

Im looking for clarification on how the solution identified the moment to be hogging, as well as the axial stress to be in compression? Also I'm confused as to how the solution came to a conclusion ...
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1answer
40 views

Max compression & Tension

I'm seeking an explanation in reference to the photo below. I'm unsure how the solution within the red box calculates the max tension of the Aluminium beam and the max compression off the Aluminium ...
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1answer
114 views

Max Tensile & Compressive Stress Question - Identify the equation

I'm struggling to identify which equation is used within the first red square. Could someone please help identify which equation was used as well as why? Thankyou!
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1answer
39 views

Water in basement plug install

I have a basement which floods, the water comes through a drain in the floor. I am therefore looking to use an HFT Pipestoppers to stop the water coming in I think the water comes from an old tank (B)...
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2answers
49 views

How were horizontal and vertical structures ensured in old times?

In modern times bubble levels and water levels are used to check if a surface if strictly horizontal/vertical. How did people ensure vertical/horizontal surfaces in older times?
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1answer
71 views

Cooling tower for nuclear power plants

Cooling towers for nuclear power plants often have the shape of a hyperboloid. At first glance, I thought that an obvious reason for this would be the smaller sectional area, meaning the tower would ...
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1answer
52 views

How do i find the effective length factor (k) for a column from this chart?

I need to find the effective length of a column (kl) from this chart which can be found in the "design of concrete structure" By Dr. Arthur Nilson. the question states "if Psi top is 1.5 and the ...
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1answer
43 views

How to professionally mount an air duct through a core hole in limestone brickwork

We need to add ventilation holes to an existing building. The holes will be core-hole drilled through a limestone brick wall. The bricks have crevices. The contractor is acting stupid and obstructive ...
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1answer
66 views

What is the axis of a pipe?

Sorry, it seems like the answer to this question is just a quick google search away; but I have not found a page defining what the axis is. My guess was that the axis of a piple is the imaginary line ...
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1answer
35 views

Along which direction is the area moment of inertia taken in bending moment equation?

Is it in the same direction of the applied load or in the co-planar perpendicular direction to the load applied?
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3answers
82 views

Truss Analysis Problem

In this case, L, theta and P are given, there will be 4 reactions at the wall? (2 horizontal and 2 vertical). $$\begin{align} \sum F_v &= 0 \therefore F_{v,B} + F_{v,A} = P \\ \sum F_h &= 0 \...
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1answer
77 views

Maximum tensile and compressive stress in a T-beam

Where does the T-beam come from? There's just a straight beam resting on two supports. And where do 10 and 80 come from? I am so confused.
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1answer
50 views

Determining the direction of internal forces in a truss

I am learning the method of joints, but there's no explanation on how to figure out the direction of internal forces in my course. How do you know that BA is tension and BC is compression?
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1answer
118 views

Is Scrooge's giant glass dome feasible in real life?

In an Uncle Scrooge (or Scrooge McDuck, not sure of the translation here) comic named "Treasure Under Glass", Scrooge orders a giant glass dome to be manufactured in order to aid his endeavours ...
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2answers
65 views

Comparing the precision work of plane surveying and geodetic surveying

In geodetic surveying, we consider the spherical geometry of the surface though the surface is not perfectly spherical. In-plane surveying, we consider a small surface area which is considered as a ...
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1answer
87 views

How will using desert sand instead of concrete sand affect my concrete recipe?

I've read that desert sand is too round for concrete mixes. But, I'm not building a dam, I'm building a 3 foot landscaping wall. I'm interested in using desert sand for the color, so this is an ...
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0answers
25 views

What injectors are typically used for mixing sewage sludge?

One typical way to heat sewage sludge digesters is to pump the sludge through heat exchangers, raw sludge is injected before or after the HX. What kind of injectors are typically used for this? I'm ...
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1answer
47 views

The formula for partial flow of Box Culvert

Refer to this document, and particular to Figure 2: I wonder what is the formula that governs the box culvert partial flow with respect to full flow? In other words, base on what formula the above ...
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1answer
45 views

Static balancing of link mechanism

So I'm trying to get to the condition as shown in the picture below, where it says that if we have zero free length springs and k1r2=k2r1, then any configuration (pose) of the link is in equilibrium. ...
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0answers
38 views

Eulerian description of fluid flow

In Eulerian description of fluid flow, we observe how the properties of the fluid are changing at a point. Since a point has zero dimension hence a zero area, how can we make sense of the 'finite ...
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33 views

Command line Macro?

AutoCAD 2017, Civil 3D - I have gone into "customize user interface" and created a new command. What would the Macro be to simply select a 3D polyline in the shape of an "L" and turn it into a square? ...