- Reginald kabo Petso asked a question:NewWhat is the impact of configuration and fixation of trafic signal post?
- Ahmed Guerine added an answer:1What is the method to find loss function in a hedging rule?
I'm working on reservoir operation releasing policy by hedging rule and i'm unable to find loss function.please suggest me what is the procedure to find loss function
I advice you to see this document. You will find what you need.
- Sujan Shrestha added an answer:3Can anyone kindly link me with guidelines of repair and restregthening of historic URM buildings?
Specially for traditional and historic buildings.
Thank you Ahmed Ebid and Dr. VikramFollowing
- Behzad Esmaeili added an answer:3What would be reliable metrics to measure the impact of a policy change to safety and quality outcomes on a construction project?
This links with my collaboration metric question. We are trying to measure the costs and benefits of investing in formal partnering activities on US highway construction contracts.
Measuring safety performance is a broad topic and depends on your objective, you can find several metrics. In CII, we classify safety indicators into two categories: lagging and leading. Lagging indicators focus on safety outcomes that can be measured after an accident happens. Some major examples in this category are:
OSHA RECORDABLE INCIDENT RATE - a mathematical calculation that describes the number of employees per 100 full-time employees that have been involved in a recordable injury or illness.
Incidence rate = (Number of injuries and illnesses X 200,000) / Employee hours worked
LOST TIME CASE RATE – a mathematical calculation that describes the number of lost time cases per 100 full-time employees in any given time frame.
LTC Rate = (Number of Lost Time Cases x 200,000)/ Number of Employee Labor Hours Worked
SEVERITY RATE – a mathematical calculation that describes the number of lost days experienced as compared to the number of incidents experienced.
SR = (Total number lost workdays)/(Total number of recordable incidents)
DART RATE - a mathematical calculation that describes the number of recordable incidents per 100 full time employees that resulted in lost or restricted days or job transfer due to work related injuries or illnesses.
DART Rate = (Total Number of DART incidents x 200,000)/( Number of Employee Labor Hours Worked)
There are several limitations related to lagging indicators. First, they are collected after an incident and we cannot use them to provide early warnings for workers. Second, accidents are infrequent events and it is possible to not have an accident in a project, even though the safety performance is not satisfactory. Third, collecting number of hours in all projects would be difficult for outside researchers. To address these problems, many people suggest to use leading indicators. Some of the main active measures are:- Number of near misses reported
- Number of behavior based safety (BBS) observations received versus the target number of BBS observations by project/month
- Number of quality JSA's as a percentage of the total number of JSA's reviewed by project/month
- Total number of Leadership walk-around's versus the total expected by project/month
- and so many others …..
While leading indicators are better in providing early warning when something is going wrong, large majority of contractors do not record them. In addition, some of these measures are subjective.
If you are trying to measure impact of policy changes on safety outcomes, I would suggest to use leading indicators, since they capture the essence of safety performance much better than lagging indicators.
Some of the good sources are:
- Hinze, J., Thurman, S., and Wehle, A. (2013). “Leading indicators of construction safety performance.” Safety Science, 51(1), 23–28.
- Hallowell, M., Hinze, J., Baud, K., and Wehle, A. (2013). ”Proactive Construction Safety Control: Measuring, Monitoring, and Responding to Safety Leading Indicators.” J. Constr. Eng. Manage., 139(10), 04013010.
- CII Report: https://www.construction-institute.org/scriptcontent/more/284_1_v1-1_more.cfm
I hope I answered your question, please let me know if you have any other question.
All the best,
Tel: (402) 472-5504
- Marcelo Leite Ribeiro added an answer:1I have a doubt in VUMAT coding?
I have a doubt in VUMAT if I calculate compliance tensor(as show in attached file) at each step and inverse it to obtain the constitutive tensor(Jacobian)and then multiply with strainInc to obtain stress increment.Similar to UMAT. Can I do this in VUMAT to calculate stressNew?.If no,why?.Then how?.
How to get stress rate as output in ABAQUS?
No, you will not update the Jacobian tensor, unless you pass the Di´ variables as a state variable and then update the Jacobian tensor.
For example, if you need to update your Jacobian tensor, you could do the following routine:
if (stateOld(km,6).lt.0) then
stateOld(km,6) = 0
flag = stateOld(km,6)
if (flag.gt.5) then
d1 = stateOld(km,1)
d2 = stateOld(km,2)
d6 = stateOld(km,3)
E11r = stateOld(km,4)
E22r = stateOld(km,5)
d2_0 = stateOld(km,8)
d6_0 = stateOld(km,9)
C CONSTITUTIVE LAW
do 10 i=1,3
do 20 j=1,3
ddsdde(i,j) = 0.0;
ddsdde(1,1) = (E11*E11r*(1.0-d1)) / (1.0-(nu12*nu21)*(1.0-d2)*
ddsdde(2,2) = (E22*E22r*(1.0-d2)) / (1.0-(nu12*nu21)*(1.0-d2)*
ddsdde(2,1) = ((1.0-d2)*nu21*E11*E11r*(1.0-d1))/(1.0-(nu12*nu21)*
ddsdde(1,2) = ddsdde(2,1)
ddsdde(3,3) = G12*(1.0-d6)
c do 100 km = 1,nblock
C Stresses calculations
stressNew(km,1) = stressOld(km,1) +
1 ddsdde(1,1) * (strainInc(km,1)) +
2 ddsdde(1,2) * (strainInc(km,2)) +
3 ddsdde(1,3) * (strainInc(km,4))
stressNew(km,2) = stressOld(km,2) +
1 ddsdde(2,1) * (strainInc(km,1)) +
2 ddsdde(2,2) * (strainInc(km,2)) +
3 ddsdde(2,3) * (strainInc(km,4))
stressNew(km,3) = stressOld(km,3) + 0.0
stressNew(km,4) = stressOld(km,4) +
1 ddsdde(3,1) * (strainInc(km,1)) +
2 ddsdde(3,2) * (strainInc(km,2)) +
3 ddsdde(3,3) * (strainInc(km,4))
If I do not update the state variable 6 in the code, The Jacobian tensor will not be update in any step.
- Mehrdad Aghagholizadeh added an answer:9How do we define Response Spectrum Functions in different damping ratios in ETABS?
In ETABS, I defined Response Spectrum Functions in UBC97, ASCE 7-10 and Eurocode 8-2004 types, howerver these Response Spectrum Functions use only 5% damping ratio. When I change the damping ratio value, the Response Spectrum is still unchanged.
How do we define Response Spectrum Functions in different damping ratios in ETABS?Following
- Rakesh Kumar asked a question:NewHow can I find the polar moment of inertia of an airfoil at different location of the blade?
I'm using Q-blade software and I have all airfoil co-ordinates but not in each section of the blade but i have thickness and position of airfoil . I attached the a file from where i took the blade data and airfoil(page no.-137)Following
- Marcelo Pitanga added an answer:8Which constitutive model is most appropriate for analysis of the interface between concrete and wall on masonry infilled reinforced concrete frames?I am using DIANA and the program has some constitutive models like friction and crush-shear-crack. The last one has a lot of input to feed the model. I have read many papers about it but I am not sure yet. Could someone help me which model to choose and how do I get the input parameters to provide the DIANA?
oh great Mohammad !!!! thanks. I'll see the paper carefully because it is very interesting.Following
- Leonard Oremont added an answer:1How implement Crank-Nicholson method into coupled PDE (Poisson Nernest Planck) ?
Let consider PDE of Nernest Planck same as below:
where t is time, X is space, A and B is the coefficients of PDE and phi is the electrical potential Ci is the concentration of specific ion. So now consider the Poisson equation as below:
e*d2phi/dX2 = F*(sigma Ci zi)
e is the permittivity of the medium, F is faraday constant, zi is the charge of specific ion.
So how we could linearized above equation by using Newton-Raphson in Crank-Nicholson scheme.
It is just quite a bit of careful algebra: Read the attached (2 page) "L.Oremont on Nernest Planck PDE.pdf" file for a how-to formulation.Following
- Wieslaw Jura added an answer:4What is your feedback on the analysis of Stresses Due to Swelling on Drilled Shafts?
I am working on a project where a drilled shaft is installed in an expansive clay soil and 6ft of soil is excavated consequently on one of the shaft. SIGMA/W and SEEP/W are being used for FEM analysis. An "insitu" analysis is made in SIGMA/W simulating the before-construction stage, and two steady-state flow analyses are performed utilizing SEEP/W. These analyses are based on the actual suction measurements (i.e. pressure head boundaries) in the beginning and a while after the project completion. The parent for the initial steady-state flow is the insitu analysis and the initial flow in turn is the parent analysis for the final steady state analysis. The excavation is simulated using a "load-deformation" analysis in SIGMA/W. The initial stress condition is implemented into this latter analysis from the insitu analysis and the initial PWP condition is coming from the initial steady-state. This stage simulates the situation right after the project completion, and thus it is expected to have zero excess pore water pressure at the shaft.
Finally, a "volume change" analysis is performed. The initial stress condition is imported from the "after completion" analysis, the initial pwp condition from the initial steady-state flow analysis (I was not sure for this, so I used the "after completion" analysis for pwp conditions as well, but the results were not different) and the final pwp condition from the final steady-state analysis.
The problem is, the lateral stress I get is ridiculously high vertical and lateral stresses on either sides of the wall. I performed a parametric study to see which parameter in the elastic-plastic material model, the soil water content function or the conductivity function contributes to the stresses, but even changing the unit weight of the soil or the young modulus variation with depth did not alter this high amount of stress. The lateral stress on the wall should be around 2,000 psf, while I get more than 20,000 psf which does not make sense for a ~60ft-deep clay.
I even sent the file to the software support, but they did not diagnose any problem with neither the file nor the boundaries assigned to the problem.
Any feedback toward this will be appreciated!
- Milad Rezaee added an answer:10Any advice on speciation calculation by PHREEQC?
I'm going to calculate the equilibrium of species and find secondary species based on master species after the equilibrium. So is it correct I put pe=4 (default of software) and put redox equal to pe and put saturation index (SI=0) for all master species.
Thanks in advance
Thank you so much because of your comments.Following
- Nguyen Duy Duan added an answer:23Which model is better for soil-structure interaction in SAP 2000 joint-springs or Link element?
I am modelling a tunnel structure (rectangular) using Soil-Structure Interaction in SAP2000. Which model is better for soil-structure interaction in SAP 2000 joint-springs or Link element?
Thank you very much for your helps.
It is available for definition of link elements in 3 directionsFollowing
- Kawa Taha Ahmed added an answer:4Is there any method to install stone columns in areas where you can't have conventional equipments?
Hi, how can a stone column be installed in areas where it is not accessible by conventional equipments. The stone columns should be installed around a foundation which is on a loose sand. Some of these stone columns should be installed in an alley, near other structures, so we can not use usual equipments. since the soil is loose, encasing is required. Thus, the installation procedure have encasing and vibration.
ibro replacement stone columns are a ground improvement technique to improve the load bearing capacity and reduce the settlement of the soil. On many occasions, it is noted that the local soil is, by nature, unable to bear the proposed structure, so the use of ground improvement techniques may be necessary. Use of stone columns is one such technique. The stone column consists of crushed coarse aggregates of various sizes. The ratio in which the stones of different sizes will be mixed is decided by design criteria.
The aforementioned crushed aggregates in the definite proportion are to be placed into the soil at regular intervals throughout the area of the land where the soil bearing capacity is to be improved. This is done either by using the dry or the wet top feed vibrators which are forced into the ground. The aggregates are then allowed to take the place of the displaced soil which exerts a pressure on the surrounding soil, hence helping to improve the soil's load-bearing capacity.
The vibrating probe breaks down the pores of the surrounding soil, thereby densifying the soil. The crushed aggregates or the gravel that is poured in takes the place of the soil and keeps up the pressure on the soil that was created by the vibrating probe.
These columns are made across the area to be built on in a grid pattern at regular intervals.Following
- Baikuntha Silwal added an answer:4Is T(braced frame) equal to T(moment frame)?
I've modeled 2D RC moment frame. Then I used diagonal braces in that frame (I've used equal DOF 1 2 for introducing hinge connection between brace and frame, braces are buckling restrained braces, I used truss element for yielding portion and elastic beam column for connecting portion).
the calculated natural period is equals for two models, and even when I use too big cross sectional area for braces the period does not change any way; Why?
The Period of the structure does not change or change insignificantly with the addition of brace elements. The change of cross section of the brace has very insignificant effect to calculate the period of the structure. The stiffness of the truss element has very little or no effect in the overall matrix of the frame in Opensees as mentioned by Behnam.Following
- Roberto Aguiar added an answer:2Can anyone suggest an article on the spectral element method for damage detection in truss structures?
I want to find a damage in truss structures by spectral element method. But I faced some problems. So I'm searching papers related to this matter.
Con el Método del Espectro de Capacidad se determina el punto de demanda (desplazamiento y aceleración en un sistema de un grado de libertad) epro después se pasa los resultados al sistema de múltiples grados de libertad y basicamante se encuentra el desplazamiento asociado. Con este valor se ingresa a la curva de capacidad sísmica que relaciona el desplazamiento lateral con el cortante (curva que es obtenida con la técnica del Pushover) y para ese punto la técnica del pushover reporta las secciones que han incursionado en el rango no lineal y el grado de incursión con lo que se halla el daño.Following
- Christian Steinke added an answer:4Who has or knows where to get real samples of any plot plans with notes?
I am elaborating exercises for future civil engineers and need authentic plot plans. Thanks
I am living in germany, so all I could try to get are german ones. I dont think that our local companies will make english labeled plans. So I guess this wont be of any help for you, right? Did you think about asking a big international company directly?Following
- AHMED ALBARRAM added an answer:14How can I deal with the velocity option in boundary condition ?
I am modeling a push-up sample regarding the composite beam. I need to apply a magnitude of load without inserting a specific amount of load or even displacement, and eventually come up with the reaction force and displacement.
I think the way to deal with this is using the Velocity/Angular velocity option in the boundary condition. How can I deal with this option.
Note: the sample I am dealing with is attached with this message
Thanks for your answer. I assume you mean applying a magnitude of load with respect to time by using am amplitude option, right? But I do not want apply an amount of either load or displacement. I need to do the opposite procedure, and know how much load could the sample resist and how much slip could occur between the steel beam and concrete.
- Ngo Ngoc-Tri added an answer:3What are the parameters to design a Container Gate?
I'm designing a gate (at the base) for a container.
According to the equation (1) the Force Required to move the gate is:
(1) Force Required = Area x Height x Bulk Density x Static Coefficient.
Is the formula correct?
About the gate.
Must be activated by a manual mechanism. (e.g. lever or wheel).
Supposing that the gate is clam-shell type. (e.g. Figure 1).
What is a suitable length for the gate arms? What are the parameters to design the arc blades?
- Boris Valdiviezo added an answer:13How do I measure workablity of fresh concrete?
I found shear vane test has been used more recently instead of slum, compacting factor and flow tests
concrete slump test is the easiest oneFollowing
- Nata Kuzlo added an answer:5Who has any articles about communication needs of future civil engineers?
I mean needs necessary for future civil engineering work, may be some surveys
thank you very muchFollowing
- Ishwar Sonar added an answer:99+Which materials have been used in the place of steel for reinforcement?It should give ductility, strength, equal to steel and cost should be less than steel
You may use bamboo splints as continuous reinforcement in concrete to replace steel. Bond stress is most important.
One can try for Nylon ropes in place of steel . But deflections will be more.
Use of coconut coir fibres is also a cost effective material for light loaded structures.
Use of coconut coir, sisal fibres, banana fibres as discontinuous , distributed fibres in plaster or thin concrete element . Some research works are carried out in these areas. But still need for more work.Following
- José Arzola-Ruiz added an answer:11Are there any standard complexity reduction methods used in systems engineering?
If so, what are they?
In my modest opinion the problem consists not in avoiding complexity, but in taking it in account solving complex problems by parts using various kind of tools.
- Abhishek Kumar Singh added an answer:15how we calculate of Sand, cement and aggregate of M20 ratio or other ratio?Ex. 1:1.5:3 is the ration of M20 and now how much sand or cement or aggregate we use in this?
Detailed analysis on M20 = 1:1.5:3 (Ratio)
As we know that during concreting when we place wet concrete , it gets harden after certain standard time( 30 mins IST & 10hrs FST), considering same it had be decided upon by Civil design Engineers to take a factor of safety ranging from 1.54 to 1.57 to counter that shrinkage.
i.e volume of dry Concrete = 1.54 to 1.57 times Volume of wet concrete.
Now calculations is as follows for 1cum(assumed) of Concrete work
ratio Sum = 1+1.5+3=5.5
Shrinkage or safety Factor =1.57 (you can take 1.54 also)
So Total volume of wet concrete required is :- 1.57cum
Volume of broken stone Require = (3/5.5) x 1.57 = 0.856 m3
Volume of sand Require = (1.5/5.5) x 1.57 = 0.471 m3
Volume of cement = (1/5.5) x 1.57 = 0.285 m3
= 0.285 x1440 = 411 kg
For 1m3 of M20 (1:1.5:3)
Broken stone = 0.856 m3
Sand = 0.472 m3
Cement = 8.22 bag.
Some important conclusion from above
8 bag of Cement is required for 1cum of concrete work in M20.
4.4 bag of cement is required for 1cum of concrete work in M10.
volume of dry concrete =1.54 times volume of wet concrete.
Thank You Folks!Following
- Reza Mahmoudi added an answer:4How can I reproduce the bifurcation diagram of the Rossler attractor while varying one parameter using MatCont?
I need to reproduce the bifurcation diagram of the Rossler attractor while varying the parameter C (period-doubling cascade) using MatCont.
I have been reading tutorials and trying on my own with no succes.
Could anyone give me some help on this topic? I would really appreciate it.
Thanks in advance.
i think you can use several loops in matlab,plot and show that...i have a code about bifurcation of logistic map...it is usefull for you...i can send you that...Following
- Mohamed Salimi added an answer:4How can I obtain frequency response function's plot in abaqus?
i'm doing a modal analysis on beam...i need plot of frequency response function ? is it possible to earn it in abaqus?
khob dobare filme youtube to bebbin:)
bbin vaghti k toye frequency domain javabo bedast miyare , to faghat bayad ino type koni:
meghdare acceleration va forceto toye frequency domain hesab mikone abaquas, bad az onja data hato biyar to excel , bad import kon to matlab, badesh faghat ino to matlab benevisi hale:
(in mesal baraye reacceptance hastesh:)
age khasti axis ham mitoni barash bezari
axis([1 800 0 inf])
- Anush K C added an answer:4How is proportioning of aggregate for marshal mix design done?
Actually am trying to get job mix formula, and now am stuck with how to carry out proportioning of aggregate. Can any expertise help me solve the problem.
The proportioning for the Marshall Mix can be done using blending procedure in such a way that the blended gradation is within the acceptable limits of your target gradation.Following
- Ashish Guruji added an answer:24Is it feasible to increase water supply in drought-affected municipal areas by recharging groundwater using surface runoff from storms?
Precipitation on impermeable surfaces in cities frequently creates a surge in runoff during storms that is difficult to capture or divert. At the same time, some of these same cities are located in areas of water shortage. Not long ago, during a discussion about water supply and drought (for example, in California), the idea of diverting storm water runoff into groundwater recharge came up.
I am not a civil engineer. I would be interested in learning about the feasibility of this idea and whether there are any designs or prototypes for this. .
In many municipal areas, combined sewage outfalls (CSOs) are being replaced by underground storage tanks and tunnels for storm water runoff. The surge in surface water is retained and held, then pumped back out later, treated (it has a significant coliform count), and discharged. What if the treated storm water were pumped into an injection well or allowed to percolate through a sand channel to recharge the aquifer instead of discharged into waterways?
There are obviously a lot of questions to be answered. Would the volume of water retained be worth it, would it be too expensive, would access to groundwater create an opportunity for inadvertent contamination from the surface, is there a mismatch between where the water falls and where the aquifers lie and therefore excessive costs for transport, etc.
I am aware of a few communities that have used direct connections with the aquifer to recharge groundwater with surging stream flow during precipitation events.
certainly, if surface runoff is excess, that can be diverted into under ground aquifer,
yes this may be some hypothetical ,surface runoff with some filter treatment, may be kept in the aquifer,there are possibility that this under ground water may reach to drought pron area!,
or directly linking with river if topography permitsFollowing
- Jacek A Koziel added an answer:6What is the best way to capture and analyze an air sample for BTEX content?.
Dan - Depending how accurate you need to be, you could consider using colorimetric tubes or electrochemical sensors (e.g., Drager, MSA, SKC), direct injection of small volume of collected gas from a gas-tight syringe into GC (if concentrations are high enough) or a PID-type detector that might be useful for screening for 'total VOCs'. We recently experimented with the use of retracted solid phase microextraction (SPME) and GC for BTEX in vehicle exhaust and fast pyrolysis (both at elevated temperatures):
Baimatova, N., J.A. Koziel, B. Kenessov. 2015. Quantification of benzene, toluene, ethylbenzene and o-xylene in internal combustion engine exhaust with time-weighted average solid phase microextraction and gas chromatography mass spectrometry. Analytica Chimica Acta, 873, 38-50.
Woolcock, P.J., J.A. Koziel, P.A. Johnston, R.C. Brown, K.M. Broer. 2015. Analysis of trace contaminants in hot gas streams using time-weighted average solid-phase microextraction: pilot-scale validation. Fuel, 153, 552-558.
Good luck with your research,
- Jiping Zhu added an answer:4To differentiate laminar and turbulent flows, different Reynold number values are mentioned in different texts. What is the correct one?I have found different Reynold number values to separate the laminar and turbulent flow regimes. For example French, R.H., mentioned in 'Open-Channel Hydraulics that it is laminar flow if Re is less than 500 and turbulent for Re greater than 12500. In another text 'Experiments in Hydraulic Engineering' by Singh, S. mentioned that if Re is less than 500 it is laminar flow and turbulent for Re greater than 2000. Similarly I have found variation in different other texts as well. What value should we take as correct? And why are there so many different ranges there?
How to use Re number to judge a gas flowing through open space like gas flow under a fan in a closed system like a box? How to define the length in this case?Following
- Ashish Guruji added an answer:7Porous concrete is better with which kind of admixture?
1. mid-range water reducing admixture
2.hydration controlling admixture
3. viscosity modifier admixture
which has better effect on porous concrete
obviously strength should be increase but not at the cost of permeability!
porous concrete is used to permit water to penetrate in the land and reducing storm water.
but as per my perception and scholars around me, suggested me that ,flyash will not serve purpose,because it will choke the perviousness of concrete,
I also agree with them,for making pervious concrete flyash not work.Following
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