Quantitative Risk Analysis

Quantitative Risk Analysis

 

This  process  is  the  second  step  in  risk  assessment.  The  purpose  of  this  process is  to numerically evaluate risks that need additional analysis after performing qualitative analysis. This evaluation is objective and the result is numerical but it depends on calculations and it lacks of human sense.   It means that these results tend to be the most accurate if revised by human sense after running the calculations.

 

1 –  Probability Distribution

Quantitative analysis utilizes computer software to model probability distribution. This can be depicted graphically using continuous distribution or discrete distribution.

Figure-1 Shows some types of continuous distribution.

Figure-1 : Continuous distribution

 

In discrete distribution, data can be represented as bars. Each bar represents a possible outcome and each outcome is assigned a probability. Figure-2 Shows a model of discrete distribution.

Figure-2 : Discrete Distribution

 

The  difference  between  continuous  and  discrete  distribution  can  be following comparison in table-1.

Table-1 : Comparison between continuous and discrete distributions

 

2- Quantitative and Modeling Techniques


Quantitative analysis utilizes simulation and modeling techniques such as sensitivity analysis, expected monetary value, and Monte Carlo.


2-1 Sensitivity Analysis


This technique shows the range of outcomes for a risk by changing only one element each time (what-if analysis) and measuring its impact. This is being done several times to evaluate the range of outcomes. It’s possible to change multiple elements by designing of experiment (DOE). Table-2 shows an example on sensitivity analysis. A common way to display these results is tornado diagram as shown in figure-3.

Table-2 : Sensitivity Analysis

Figure-3 : Tornado Diagram

 

2 -2 Expected Monetary Value

 

This technique calculates outcomes considering both probability and impact. It’s used to  make  decisions after  gathering  data  on  two  or  more  alternatives.  It  depends basically  on  the  impact  of  each  decision and  the  probability  that  it  may  happen.

Multiplying  impact by  its  probability  will  result  the expected monetary value.

Comparing  these values  will facilitate  taking  decision.  This  technique  uses the decision tree analysis as a  graphical method to represent alternatives and their impact/probability. Figure-4 shows an example of decision tree analysis.

Figure-4  Decision Tree Analysis

2-3  Simulation & Modeling

 

This technique utilizes Monte Carlo technique as a simulation tool. Project model is computed several times with the input of cost estimates or activity durations that are being  choose  at  random  for  each  time  from  the  probability  distributions  of  these variables. A  chart of total cost or total duration is then drawn. Figure-5 shows an example of this chart.

Figure-5 : Monte Carlo Simulation for Project Cost

 

3 –  Risk Register Update


At this point, the risk register will be updated with the followings
1- Probabilistic analysis of the project
2- Quantified probability of meeting project objectives
3- Prioritized list of quantified risks
4- Overall project risk (Risk Exposure)

 

 

 

Qualitative Risk Analysis

Qualitative Risk Analysis

 

This process is the first process in risk assessment. The purpose of this process is to evaluate each risk you have evaluated in the last process. This evaluation is subjective and the result is not numerical. However, ths evaluation is almost accurate because it depends on human sense that is buit up on experience. The output of this process is the probability and impact assessement of each identifie risk.

While performing this analysis, you may use some tools and techniques such as risk categorzation and probability and impact matrix. Risk categorzation utilises the risk categories that have been developed in risk planning process. Probability and impact matrix defines combinations of probability and impact that lead to rating risks as low, moderate, and high priority. Figure-1 shows an example of probability and impact matrix.

 

Figure-1 Probability and impact matrix

The subsequent decision of analyzing a risk through this process could be one of the following:
1- This risk is a minor risk and it should be put in a watch list.
2- This risk needs more analysis and it should be analyzed quantitatively.
3- This risk is urgent and it should go quickly to response planning.
4- The qualitative analysis of this risk is enough and no need for further analysis.
Hence this risk should go to response planning.

Figure-2 shows a diagram expressing the work flow of these steps.

Figure-2 Risk Assessment Mechanism

By the end of this process, risk register is being updated with the results from qualitative analysis. This may include ranking, grouping by category, risks require quick response, risks require additional analysis, and low priority risks that will be listed in watchlist.

Table-1 shows an example of risk register up to this point.

Table-1 Risk Register (Updated after qualitative analysis)

Risk Identification

Risk Identification

 

The next planning effort in risk management after risk planning is risk identification. The purpose of this process is to identify all potential risks in the project regardless of their probability or their impact. Assessment will be done later in a following process.


Identification is being done using various techniques such as information gathering techniques, documents review, checklist analysis, assumption analysis, and SWOT analysis.


The output of this process is a table contains all identified potential risks with initial information concerning every item of them. This table is known as risk register. Through the following clauses, we are going to discuss these techniques and the risk register.

 

1 – Information Gathering Analysis


Examples of data gathering techniques are brainstorming, Delphi technique, interviewing, root cause analysis, and mind mapping. Figure-1 shows an example of mind mapping

Figure-1 : Mind Mapping for Potential Project Risks

 

2-  Documentation Review


One of the most effective methods to identify a significant number of potential risks is to review project documents. This method allows you to explore and discover most areas of project activities starting from the very early milestones of project initiation passing with all the phases, decisions, evaluations, and studies of the project. These  documentation includes project charter, project management plan and its subsidiary plans, WBS, time schedule, activity duration estimates, activity cost estimates, stakeholder register, contracts, and procurement documents. The following chart is a hierarchy of potential project documents.

 

3 –  Checklist Analysis


This checklist is a list contains predefined risks that you can check them if they are potential in your project. It can be developed based on historical information from past projects. The lowest level of RBS can be used as a checklist as in Figure-2. It’s very quick to use it and you will have a lot of risks identified. However, it should not be the only tool that is being used for this purpose. The reason behind this advice is that usually there are risks that are not listed in this checklist. Hence if you only depend on this checklist, other risks will be neglected.

 

Figure2 : Risks Checklist

 

4-  SWOT Analysis


SWOT analysis is a famous technique that is being used to identify and evaluate the strength and weakness in the project and organization in order to find out expected opportunities and threats. Table-1 shows an example of SWOT analysis.

Table-1: SWOT Analysis

5 – Risk Register

Risk register is an ouput of all risk management processes that come after risk planning. It’s a dynamic database that contains all the identified risks and is being filled with the information regarding these risks such as description, category, propability, impact, planned response, assigned person for action, risk status, retained reserve for this risk, …etc

Through the process of identify risks, this table is being filled with risks in addition to the root cause and initial proposed response. Table-2 shows an example of risk register till this point.

 

Table-2 : Risk Register (Initial View)

 

 

Risk Planning

Risk Planning

 

Usually, risk plan is the first effort that is being done through project risk management.
However, in some projects, the top management in the organization identifies high level risks in the project charter and these high level risks are the input for the project manager that clarify an image of what risks are significant and  important for the top management.

Risk plan is a subsidiary plan of project management plan that describes how risk management activities will be managed throughout the project phases. This plan performs as a guide of how you will accomplish all the activities of risk management. It defines the tools and approaches that will be used, roles and responsibilities, estimated budget for these activities, risk categories, risk definitions, reporting formats, and auditing procedures.


Through the next paragraphs, we will show examples for some of these components of risk management plan.


1 – Tools & Approaches


Risk management activities may be done manually or using computer software programs. These software programs expedite, facilitate, and fully control the of risk management activities. These programs can be integrated with other organization systems such as scheduling, costing, and ERP systems. The capabilities of these programs are not only for calculation and assessment; however it can track and communicate responsibilities to the team assigned for these tasks and also for the management to be able to follow the status and take actions.


2 –  Roles and Responsibilities


Table-1 shows an example for the roles and responsibilities.

Team member
Name 		Role Responsibilities
Ahmed Arafa Risk
Manager		 1. Develop the risk management plan
2. Manage the risk management team.
3. Follow up that risk management activities are being done
with the valid manner in the right time.
4. Monitor contingency reserve and maintain the sufficiency
of monetary in reserve fund.
5. Report on risk management activities.
Ayman Nagy Risk
Software
Admin		 1. Administrate the risk management program.
2. Maintain and monitor the privilege of users.
Wael Samy Risk
Engineer		 1. Share in the identification of risks.
2. Develop the qualitative and quantitative analysis.

Table-1 : Roles and Responsibilities


3 –  Timing and Frequency


Risk management activities are being done according to a time scheduling that is being developed by the risk manager and in conformity of project management vision.


Figure-1 is an example of risk management activities time scheduling.

Figure-1 : Risk Activities Time Schedule


Risk management meetings could be determined to be as a separate meeting and held on weekly, bi-weekly, or monthly basis. The common practice is that risk management activities are being discussed in the progress status weekly meeting.

 

4 –  Risk Categories


Risk Categories can be illustrated in a list or a risk breakdown structure. Figure-2 is an example of risk breakdown structure.

 

Figure-2 : Risk Breakdown Structure

 

5- Risk Definition


This is the classification criteria that will be used further in order to qualitatively assess risks. Table-2 shows an example of these limits.

Table-2 : Risk Classification Limits

 

6 –  Risk tracking and Reports format


This defines how risks will be tracked during project phases; and the formats of risk reports that will be used to communicate risk information through vertical and horizontal communication channels.

Risk Processes

Risk Processes

 

Association for the Advancement of Cost Engineering (AACE) structured the risk management steps as “(1) Planning, (2) Identification, (3) Assessment, (4) Analysis, (5) Mitigation, and (6) Follow-Up” (Skills & Knowledge of Cost engineering, Fifth Edition Revised, 2007, Page 31.2).


Project Management Institute (PMI) defines the risk management processes as “(1) Planning, (2) Identification, (3) Qualitative Analysis, (4) Quantitative Analysis, (5) Planning Response, (6) Monitor and Control.” (PMBOK Guide, 2013, Page 312)

 

What is Risk Management

What is Risk Management

 

The “Risk Management” phrase is used in several fields with different significance. The most common use of this expression is the “Pure Risk” which is used in the aspects of safety and health referring to the pure risk. The risk management in RMP-PMI is another type which is referred to as “Business Risk”. The difference between those two types can be shown as follow:


• Pure Risk: The risk of loss (fire, theft, injury… etc.) that is insurable.
• Business Risk: The risk of gain or loss that is concerned to business threats or opportunities.


Project Management Institute (PMI) defines risk as “an uncertain event or condition that, if it occurs, has a positive or negative effect on one or more project objectives such as scope, schedule, cost, and quality”. (PMBOK Guide, 2013, Page 310) where the uncertainty is lack of knowledge that reduces confidence in conclusions.


The common factors of risk management are:
– Probability: How much percent risk may occur
– Impact: The range of possible outcomes such as time, money …etc.
– Timing: When the risk is expected to take place.
– Frequency: How often this risk is expected to happen


Through risk management you try to increase probability and impact of opportunities, while decrease probability and impact of threats. This action depends on the risk culture of the decision taker which is referred to as risk tolerance. Risk tolerance defines the thresholds that when a risk exceeds, it becomes unacceptable. The most known tolerances are:


• Risk Averse: Someone who doesn’t want to take risks.
• Risk tolerant: Someone who doesn’t perform a great effort to search for risk, however when the risk comes to him, he exploit it.
• Risk Seeker: Someone who spends a lot of time searching for risks.

What is better steel or concrete?

What is better steel or concrete?

 

Construction projects require many decisions. A key decision is to find the most effective option, as well as determining which process could produce ideal results.

Take a look at this breakdown. This example weighs the pros and cons of Structural Steel versus Concrete.

Costs

Structural Steel: A large majority of all steel manufactured today comes from recycled materials; A992 steel. This recycling usage makes the material much cheaper when compared to other materials. Although the price of steel can fluctuate, it typically remains a less expensive option compared to reinforced concrete.

Concrete: A large cost benefit to concrete is the fact that its price remains relatively consistent. On the other hand, concrete also requires ongoing maintenance and repairs, meaning added costs throughout its lifetime. Supply-and-demand may also impact the availability of concrete. Even though it can be poured and worked with directly onsite, the process to completion can be lengthy and could accrue higher labor costs.

Strength

Structural Steel: Structural steel is extremely strong, stiff, tough, and ductile; making it one of the leading materials used in commercial and industrial building construction.

Concrete: Concrete is a composite material consisting of cement, sand, gravel and water. It has a relatively high compressive strength, but lacks tensile strength. Concrete must be reinforced with steel rebar to increase a structure’s tensile capacity, ductility and elasticity.

Fire Resistance

Structural Steel: Steel is inherently a non-combustible material. However, when heated to extreme temperatures, it’s strength can be significantly compromised. Therefore, the IBC requires steel to be covered in additional fire resistant materials to improve safety.

Concrete: The composition of concrete makes it naturally fire resistant and in line with all International Building Codes (IBC). When concrete is used for building construction, many of the other components used in construction are not fire resistant. Professionals should adhere to all safety codes when in the building process to prevent complications within the overall structure.

Sustainability

Structural Steel: Structural steel is nearly 100% recyclable as well as 90% of all Structural Steel used today is created from recycled steel. Due to its long lifespan, steel can be used as well as adapted multiple times with little to no compromise to its structural integrity. When manufactured, fabricated and treated properly, structural steel will have a minimal impact on the environment.

Concrete: The elements within concrete are natural to our environment, reducing the harm to our world. Concrete may be crushed and used in future mixtures. This type of recycling can reduce a presence of concrete in landfills.

Versatility

Structural Steel: Steel is a flexible material that can be fabricated into a wide array of designs for endless applications. The strength-to-weight ratio of steel is much higher when compared to other affordable building materials. Steel also offers many different aesthetic options that different materials, such as concrete, cannot compete with.

Concrete: Although concrete can be molded into many different shapes, it does face some limitations when it comes to floor-to-floor construction heights and long, open spans.

Corrosion

Structural Steel: Steel may corrode when it comes into contact with water. If left without proper care, it could affect the safety and security of a structure. Professionals should care for the steel with such processes such as water-resistant seals and paint care. Fire-resistant features may be included when water-resisting seals are applied.

Concrete: With proper construction and care, reinforced concrete is water resistant and will not corrode. However, it’s important to note that the steel reinforcement inside should never be exposed. If exposed, the steel becomes compromised and can easily corrode, compromising the strength of the structure.

Reference : blog.swantonweld.com

Concrete calculator formula

Concrete calculator formula

What is concrete?

Concrete is one of the most commonly used building materials.

Concrete is a composite materialmade from several readily available constituents(aggregates, sand, cement, water).

Concrete is a versatile material that can easily be mixedto meet a variety of special needs and formed to virtually any shape.

What you should know Before Estimating :

Density of Cement       = 1440 kg/m3
Sand Density                  = 1450-1500 kg/m3
Density of Aggregate   = 1450-1550 kg/m3

How many KG in 1 bag of cement                                 = 50 kg
Cement quantity  in litres in 1 bag of cement          = 34.7 litres
1 Bag of cement in  cubic metres                                  = 0.0347 cubic meter
How many CFT (Cubic Feet)                                            = 1.226 CFT
Numbers of Bags in 1 cubic metre cement               = 28.8 Bags

Specific gravity of cement   = 3.15
Grade of cement  =  33, 43, 53
Where 33, 43, 53 compressive strength of cement in N/mm2

M-20 = 1 : 1.5 : 3  = 5.5, (Cement : Sand : Aggregate)
Some of Mix is – 5.5

Where, M   = Mix
20  = Characteristic Compressive strength

Consider volume of concrete = 1m3

Dry  Volume of Concrete = 1 x 1.54 = 1.54 m3    (For Dry Volume Multiply By 1.54)

Calculation for Cement, Sand and Aggregate quality in 1 cubic meter concrete:

 

  • CALCULATION FOR CEMENT QUANTITY

Cement=  (1/5.5) x  1.54    = 0.28 m3   ∴ 1 is a part of cement, 5.5 is sum of ratio
Density of Cement is 1440/m3

= 0.28  x 1440 = 403.2 kg

We know each bag of cement is 50 kg
For Numbers of Bags =   403.2/50     = 8 Bags

 We Know in one bag of cement = 1.226 CFT

 For Calculate in CFT (Cubic Feet) = 8  x 1.225      = 9.8 Cubic Feet

  •   CALCULATION FOR SAND QUANTITY

Consider volume of concrete = 1m3

Dry  Volume of Concrete = 1 x 1.54 = 1.54 m3

 Sand=  (1.5/5.5) x 1.54    = 0.42 m3   ∴ 1.5 is a part of Sand, 5.5 is sum of ratio

Density of Sand is 1450/m3

For KG = 0.42 x 1450 = 609 kg

 As we know that 1m3 = 35.31 CFT

For Calculation in Cubic Feet   = 0.42 x 35.31 = 14.83 Cubic Feet

 

  • CALCULATION FOR AGGREGATE QUANTITY

Consider volume of concrete = 1m3

Dry  Volume of Concrete = 1 x 1.54 = 1.54 m3

Aggregate =   (3/5.5) x 1.54 = 0.84 m3 ∴ 3 is a part of cement, 5.5 is sum of ratio

Density of Aggregate is 1500/m3  

Calculation for KG = 0.84 x 1500   = 1260 kg

As we know that 1 m3 = 35.31 CFT

Calculation for CFT  = 0.84 x 35.31 = 29.66 Cubic Feet

Concrete Quality calculation sheet download

Calculation for Cement, Sand  quality in mortar  for Plaster:

 

Area of brick wall for plaster = 3m x 3m =9m2

Plaster Thickness = 12mm (Outer-20mm, Inner 12mm)

Volume of mortar = 9m2  0.012m            = 0.108m3

Ratio for Plaster Taken is                             = 1 : 6

Sum of ratio is                                                   = 7

 

Calculation for Cement Volume

Dry Volume of Mortar = 0.108  1.35 = 0.1458 m3

Cement= (1/7) = 0.0208 m3  

Density of Cement is 1440/m3

= 0 1440              = 29.99 kg

We know each bag of cement is 50 kg

= (29.99/50)        = 0.599 Bags

 

Calculation for Sand Volume

Sand = (6/7) x 0.1458      = 0.124m3

Density of Sand is 1450/m3

= 0 1450                = 181.2 kg

Now we find how many CFT (Cubic feet) Required

 As we know that 1m3 = 35.31 CFT

= 0.124*35.31

               = 4.37 CFT (Cubic Feet)

 

Plaster calculation sheet download

Reference : tutorialstipscivil.com

Beam on Elastic Foundation Analysis Sheet

Beam on Elastic Foundation Analysis Sheet

 

BOEF is a spreadsheet program written in MS-Excel for the purpose of analysis a finite length beam with free ends supported continuously on an elastic foundation. This program is ideally suited for analyzing a soil supported beam, a combined footing, or a strip of a slab or a mat. Specifically, the beam shear, moment, deflection, and soil bearing pressure are calculated for 100 equal beam segments, as well as the maximum values. Plots of both the shear, moment, and soil bearing pressure diagrams are produced, as well as a tabulation of the shear, moment, deflection, and bearing pressure for the beam.

Program Assumptions and Limitations:

1. The following reference was used in the development of this program (see below):

“Formulas for Stress and Strain” – Fifth Edition – by Raymond R. Roark and Warren C. Young, McGraw-Hill Book Company (1975), pages 128 to 146.

2. This program uses the equations for a “finite-length” beam in the analysis. This usually gives very similar to exact results for a “semi-infinite” beam which has had end-corrections applied to “force” the moment and shear values to be equal to zero at the ends. (Note: a “semi-infinite” beam is defined as one that has a b*L value > 6.)

3. This program uses the five (5) additional following assumptions as a basis for analysis:

  • Beam must be of constant cross section (E and I are constant for entire length, L).
  • Beam must have both ends “free”. (“Pinned” or “fixed” ends are not permitted.)
  • Elastic support medium (soil) has a constant modulus of subgrade, K, along entire length of beam.
  • Applied loads are located in the center of the width, B, of the beam and act along a centroidal line of the beam-soil contact area.
  • Bearing pressure is linearly proportional to the deflection, and varies as a function of subgrade modulus, K.

4. This program can handle up to twelve (12) concentrated (point) loads, a full uniformly distributed load with up to six (6) additional full or partial uniformly distributed loads, and up to four (4) externally applied moments.

5. Beam self-weight is NOT automatically included in the program analysis, but may be accounted for as a full uniformly distributed applied load. Beam self-weight will only affect the deflection and bearing pressure, and not the moment or shear.

6. This program will calculate the maximum positive and negative shears, the maximum positive and negative moments, the maximum negative deflection, and the maximum soil bearing pressure. The calculated values for the maximum shears, maximum moments, deflection, and bearing pressure are determined from dividing the beam into 100 equal segments with 101 points, and including all of the point load and applied moment locations as well.

7. The user is given the ability to input four (4) specific locations from the left end of the beam to calculate the shear, moment, deflection, and bearing pressure.

8. The plots of the shear, moment, and bearing pressure diagrams as well as the displayed tabulation of shear, moment, deflection, and bearing pressure are based on the beam being divided up into 100 equal segments with 101 points.

9. This program contains numerous “comment boxes” which contain a wide variety of information including explanations of input or output items, equations used, data tables, etc. (Note: presence of a “comment box” is denoted by a “red triangle” in the upper right-hand corner of a cell. Merely move the mouse pointer to the desired cell to view the contents of that particular “comment box”.)

Wind loading analysis sheet

Wind loading analysis sheet

 

Program Description:

“ASCE710W” is a spreadsheet program written in MS-Excel for the purpose of wind loading analysis for buildings and structures per the ASCE 7-10 Code.  Specifically, wind pressure coefficients and related and required parameters are selected or calculated in order to compute the net design wind pressures.    Program is based on Alex Tomanovich’s “ASCE705W” program and modified by David Taylor and William Fultz.

This program is a workbook consisting of nine (7) worksheets, described as follows:

Worksheet NameDescription
Doc This documentation sheet
MWFRS (Low-Rise)    Main Wind-Force Resisting System for low-rise buildings with h <= 60’
MWFRS (Any Ht.)    Main Wind-Force Resisting System for buildings of any height
Wall C&C    Analysis of wall Components and Cladding
Roof C&C    Analysis of roof Components and Cladding
Open Structures (no roof)    Analysis of open structures without roofs
Wind Map    Basic wind speed map (Figure 26.5-1 of ASCE 7-10 Code)

Program Assumptions and Limitations:

1.  Worksheet for “MWFRS (Low-Rise)” is applicable for low-rise buildings as defined in Section 26.2.
2.  Worksheets for “MWFRS (Any Ht.)”, “Wall C&C”, and “Roof C&C” are applicable for buildings with mean roof heights of up to 500 feet.
3.  In worksheets for “MWFRS (Any Ht.)”, “Wall C&C”, and “Roof C&C” the user may opt to utilize user designated steps in height, ‘z’, in determining the wind pressure distribution.
4.  Worksheets for “MWFRS (Any Ht.)”, and “Open Structures” can handle “rigid” as well as “flexible” buildings and structures.  For “rigid” buildings or structures, this program uses the smaller value of either 0.85 or the calculated value from Section 26.9.3 of the Code for the gust effect factor, ‘G’.  For “flexible” buildings or structures, this program calculates the gust effect factor, ‘Gf’, per Section 26.9.4 of the Code based on the assumed formula for the fundamental period of vibration from Section 12.8.2.1 of the Code, where the exponent ‘x’ in the formula T = Ct*h^x is assumed to be 0.75.
5.  Worksheets for “Wall C&C” and “Roof C&C” are applicable for flat roof buildings, gable roof buildings with roof angles <= 45 degrees, and monoslope roof buildings with roof angles <= 3 degrees.
6.  Worksheet for “Open Structures” is applicable for open structures without roofs up to 500 feet tall.  This can be utilized for open process-type structures as well as pipe/utility racks and bridges.
7.  This program uses the equations listed in the reference, “Guide to the Use of the Wind Load Provisions of ASCE 7-02” for determining the external wind pressure coefficients, ‘GCp’, used in the Wall C&C and Roof C&C worksheets.  (Note: a version of this document applicable to the ASCE 7-10 Code was not available at the time of writing this program.)
8. This program contains numerous “comment boxes” which contain a wide variety of information including explanations of input or output items, equations used, data tables, etc.  (Note:  presence of a “comment box” is denoted by a “red triangle” in the upper right-hand corner of a cell.  Merely move the mouse pointer to the desired cell to view the contents of that particular “comment box”.)

 

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