The PMP Certification Process Overview

The PMP Certification Process Overview

 

The PMP® Certification Process and the requirements for becoming a PMP® are quite complicated if you haven’t taken any PMI exams (like CAPM® or PMI-ACP®) before. Reading the PMP® Handbook alone will not help you much as you will still have some questions unanswered.

A) Fulfil PMP® credential requirements:

  1. Must have enough project management experience as stipulated by PMI
    • For secondary degree holders (e.g. high school diploma, associate’s degree): need to have at least5 years of project management experience and a minimum of 7,500 hours leading and directing projects
    • For four-year degree holders (e.g. bachelor’s degree): need to have at least 3 years of project management experience and a minimum of 4,500 hours leading and directing projects
  2. Have the required 35 Hours of Project Management Education
    • Any education on project management offered by a formal education provider taken at any time before the PMP® exam will satisfy this requirement, e.g. a course in your degree curriculum about project management with a length of more than 35 hours;
    • The course on project management is NOT required to be based on PMBOK® Guide. BUT taking a course based on PMBOK® Guide will help you also in your PMP® preparation (try to find a PMP® exam prep course provided by a PMI Registered Education Provider (R.E.P.)that is accredited by PMI, more on that later).

What is project management experience as recognized by PMI?

  • NO need to carry the job title ‘project manager‘ but must be assigned the responsibility of managing and taking care of projects.
  • The experience is about project management (as defined in the PMBOK® Guide) and not just carrying out project works managed by others.
  • Must have experience in all the lifecycle phases of projects (i.e. 5 process groups of the project management lifecycle, including initiating, planning, directing, monitoring & controlling and closing the project). PMI does not require you to have experience with the 5 process groups from every project. That means you can just involve in initiating in Project A, closing in Project B and all 3 others in Project C.
  • You may consider the Certified Associate in Project Management Certification (CAPM®) offered by the Project Management Institute (PMI) if you have not accumulated the required project management experience. The CAPM® is also based on the PMBOK® Guide (more on factual memorization) but there are no experience requirements.

B) Apply for the PMP® certification online:

  1. The most convenient way to apply for the PMP® exam is through the online system at http://certification.pmi.org.
  2. Sign up for a user account first. After which you can log in and begin filling in the PMP® application form. The information entered on the PMP® application form will be stored on PMI’s web server for up to 90 days. You will get an email reminder from PMI a few days before that period will expire and all the information be deleted.
  3. Read the article on common mistakes of PMP® Application and how you can avoid them.
  4. [Optional but highly recommended] Become a member of PMI. Though it is not required to become a paying member of PMI to take the PMP® exam, being a member allow you to enjoy discounted PMP® and other certification fees, a free downloadable copy of PMBOK® Guide and many online PMP® exam reference books. The PMI annual membership fee is US$129 plus US$10 of first-time registration fee. The money you will save by becoming a member will be much more than the cost of the membership fee for the first year.
  5. After you have completed the online application form, submit it and wait for the approval to sit for the PMP® exam from PMI (in the form of an email).
  6. You can now pay the PMP® certification fee online (US$405 for members and US$555 for non-members). Remember to pay $139 for the membership fee first if you haven’t before paying the PMP® certification fee, you will get an instant saving of US$16.
  7. [Selected randomly by PMI] If you are so fortunate to be chosen for an audit by PMI, you will get a notification email immediately after you have paid the exam fee. Act as fast as possible to send them all the required documents (e.g. academic certificates, 35 hours of project management education certificate, proof of working experience, etc.). Otherwise, you will be given an email authorizing you to schedule your PMP® exam at Prometric website.

C) Schedule, attempt and pass the PMP® exam:

  1. Though you are given a 1-year validity period during which you can schedule the PMP® exam at any time, it is advisable to schedule the PMP® Exam at Prometric website as soon as possible. This arrangement has two benefits:
    • Exam places are limited, the faster to schedule, the more likely you can schedule the exam at a date and time you prefer;
    • Having scheduled the exam will give you a tangible target for you to prepare consistently for the PMP® exam.
  2. Prepare and study well for the PMP® exam by making use of the PMBOK® Guide guide, a PMP® study guide as well as numerous PMP® practice exams.
  3. On the date of the exam, arrive at the exam centre early. Relax and enjoy the exam.
  4. You will be notified of the exam result immediately after the exam. The center staff will give you a printed proof of your exam achievement. If it is a pass, congratulations, you are immediately a PMP®! If, unfortunately, you fail the first try, make plans to retake the exam. You can have up to 2 more chances to take the PMP® exam within the 1-year validity period (though you must pay the re-exam fee separately).

D) Obtain PMP® PDU for re-certification

  1. The PMP® certificate will be mailed to you within 6-8 weeks.
  2. The first benefit of becoming a PMP® is that you can request a PMP® lapel pin free of charge (details will be emailed to you several days after you have passed).
  3. If you pass the PMP® exam, you are immediately a PMP® and your 3-year PDU re-certification cycle begins. Collect at least 60 PDUs per 3-year cycle to allow you to renew your PMP® credential.
  4. You can make use of PMI’s online system to report PDUs to PMI. When you have accumulated enough PDUs, PMI will send you a renewal notice. The renewal fee is US$60 for members and US$150 for non-members.

What’s Next?

If you fulfil the PMP® requirements and are eligible for the PMP® exam, you should next try to understand how much time, money and efforts are needed to get your PMP® title. This is the second most pressing question any PMP® aspirants would ask. 

PMP®️ Domain Information & Overview

PMP®️ Domain Information & Overview

 

Introduction

Welcome back to this series on the Project Management Professional (PMP)®️ certification. In this article, we will cover everything you need to know about the domains/performance areas covered in the PMP examination.

First off, let’s start with an explanation of what domains are.

What Domains Are Covered on the PMP Exam?

Project management is defined as the application of knowledge, skills, tools and techniques to project activities/tasks to meet project requirements. The project activities/tasks a project manager has to perform are divided into five performance areas or domains. These are the five domains that are covered in the PMP exam to ensure you have all the competencies needed to successfully manage any project.

The domains are:

Initiating

This domain covers defining a new project or phase and initial scope, getting authorization, getting initial financial commitment and identifying stakeholders.

Planning

This domain covers defining the scope, objectives and a clear course of action that will be taken to achieve the objectives. All the planning information is stored in the project management plan, which often needs to be revisited if a change happens.

Executing

This domain covers executing the work defined in the project management plan, coordinating people and resources.

Monitoring and Controlling

This domain covers tracking and reviewing the progress and performance of the project and initiating changes if necessary.

Closing

This domain covers finalizing all activities and formally close the project. It may involve getting client acceptance and documenting lessons learned or changes to assets.

How Often Are the Domains Updated?

In order to ensure that the Project Management Professional certification evolves with the profession and reflects competencies needed by present-day project managers in their day-to-day activities, the Project Management Institute (PMI®️) conducts role delineation studies (job analysis) every five to seven years (PMP Certification Handbook, 2017). The role delineation study is performed by an independent party and is validated by volunteer project managers all over the world.

The outcome of the role delineation study may indicate changes to the terminology, tasks, knowledge and skills needed by project managers. This will result in an update to the domains, which domains are most important and how many questions are allocated within each domain in the PMP examination. The changes to the domain are outlined in the PMP exam content outline, which was last published in June 2015. A change in the PMP exam content outline results in a change in the PMP exams.

It is important to note that even though the PMP exam is based on the PMP exam content outline, sometimes the PMP exam also changes even when the exam content outline does not change: for example, when a new edition of the Project Management Book of Knowledge (PMBOK) is released. The PMP exam was last updated on March 26, 2018

How Much is Each Domain Worth on the Exam?

The number of questions from each domain in the PMP exam depends on the outcome of the last role delineation study and which areas are considered most important.

The exam has 200 multiple-choice questions. 175 of them are scorable while the remaining 25, called pre-test questions, are not. Pre-test questions allow PMI to monitor the question performance before adding them to the official exam questions. The 175 scorable questions are broken down into the following percentages:

Initiation: 13%

Planning: 24%

Executing: 31%

Monitoring and Controlling: 25%

Closing: 7%

What Topics Are Covered in Each Domain?

PMP Domains are groups of tasks that the project manager needs to do in order to manage projects and the knowledge or skills needed to do these tasks efficiently. Some of these knowledge areas and skills cross multiple domains and tasks. In this section, we will outline which tasks, knowledge areas and skills are needed in each domain.

Domain 1: Initiating

The first domain on the PMP is called Initiating. The aim of this domain is to test your ability to perform the tasks needed to initiate a project or a phase of a project. Before a project can start, it needs to be determined that the idea for the project and its main objectives are feasible. The project manager then needs to perform several tasks to ensure the project can be completed effectively and get approval to start the project. There are eight tasks within the initiating domain. They are:

  • Performing project assessment to determine feasibility
  • Identifying key deliverables based on business requirements
  • Performing stakeholder analysis
  • Identifying high-level risks, assumptions and constraints
  • Developing the project charter
  • Getting approval of project charter from sponsor
  • Conducting benefit analysis with relevant stakeholders
  • Informing stakeholder of approved project charter

Specific knowledge and skills needed in this area include: analytical skills, benefit analysis techniques, elements of a project charter, estimation tools and techniques and strategic management.

Domain 2: Planning

The second domain on the PMP is called Planning. The aim of this domain is to test your ability to perform tasks needed to outline a clear course of action for achieving the objectives of the project. For example: creating a schedule, determining how finances will be managed, determining how change will be managed and so forth. All the planning information is stored in the project management plan. There are 13 tasks within the planning domain:

  • Reviewing and assessing detailed project requirements, constraints and assumptions with stakeholders
  • Developing a scope management plan
  • Developing a cost management plan
  • Developing the project schedule
  • Developing the human resource management plan
  • Developing the communications management plan
  • Developing the procurement management plan
  • Developing the quality management plan
  • Developing the change management plan
  • Developing the risk management plan
  • Presenting the project management plan
  • Conducting the kick-off meeting and communicating relevant information
  • Developing the stakeholder management plan

Specific knowledge and skills needed include: change management planning, cost management planning, inclusion of project budgeting tools and techniques, communications planning, contract types and selection criteria, estimation tools and techniques, human resource planning, lean and efficiency principles, procurement planning, quality management planning, requirements gathering techniques (e.g., planning sessions, brainstorming and focus groups), regulatory and environmental impacts assessment planning, risk management planning, scope deconstruction (e.g., WBS, scope backlog) tools and techniques, scope management planning, stakeholder management planning and time management planning, including scheduling tools and techniques and workflow diagramming techniques.

Domain 3: Executing

The third domain on the PMP is called Executing. The aim of this domain is to test your ability to perform the tasks needed to carry out the course of action set out in the project management plan. The project manager needs to coordinate resources, ensure they understand and implement the plan, manage how project information is communicated and manage the relationship with stakeholders. There are seven tasks within the executing domain. They are:

  • Acquiring and managing project resources by following the human resource and procurement plan
  • Managing task execution based on the project management plan
  • Implementing the quality management plan
  • Implementing approved changes and corrective actions by following the change management plan
  • Implementing approved actions by following the risk action plan
  • Managing the flow of information by following the communication plan
  • Manage stakeholder relationship by following the stakeholder management plan

Specific knowledge and skills needed include: continuous improvement processes, contract management techniques, elements of a statement of work, interdependencies among project elements, project budgeting tools and techniques, quality standard tools and vendor management techniques.

Domain 4: Monitoring and Controlling

The fourth domain on the PMP is called Monitoring and Controlling. The aim of this domain is to test your ability to perform the tasks needed to track and review the progress and performance of the project. The project manager needs to do everything necessary to make sure the project is on track and that deliverables meet the expected standard. There are seven tasks within the monitoring and control domain. They are:

  • Measuring project performance
  • Managing changes to project following change management plan
  • Verifying that project deliverables conform to the standards in the quality management plan
  • Monitoring and assessing risks
  • Reviewing issue logs
  • Capturing and analyzing lessons learned
  • Monitoring procurement activities according to the procurement plan

Specific knowledge and skills needed include: performance measurement and tracking techniques (e.g., EV, CPM, PERT, trend analysis), process analysis techniques (e.g., LEAN, Kanban, Six Sigma), project control limits (e.g., thresholds, tolerance), project finance principles, project monitoring tools and techniques, project quality best practices and standards (e.g., ISO, BS, CMMI, IEEE), quality measurement tools (e.g., statistical sampling, control charts, flowcharting, inspection, assessment), risk identification and analysis techniques, risk response techniques and quality validation and verification techniques.

Domain 5: Closing

The fifth and last domain on the PMP is aptly called Closing. The aim of this domain is to test your ability to perform tasks needed to finalize all activities and formally close the project. The project manager needs to ensure that the client accepts the deliverables and document lessons learnt for future projects. There are seven tasks within the closing domain. They are:

  • Obtain final approval of project deliverables from relevant stakeholders
  • Transfer ownership of project deliverables to assigned stakeholders
  • Obtain financial, legal and administrative closure
  • Prepare and share final project report according to the communications management plan
  • Collate lessons learned and conduct a project review
  • Archive project documents and materials
  • Obtain feedback from relevant stakeholders

Specific knowledge and skills needed include: archiving practices and statutes, compliance (statute/organization), contract closure requirements, close-out procedures, feedback techniques, performance measurement techniques (KPI and key success factors), project review techniques and transition planning techniques.

Further knowledge areas and skills

There are additional knowledge and skills that cut across all 5 domains. They include: active listening; applicable laws and regulations; benefits realization; brainstorming techniques; business acumen; change management techniques; coaching, mentoring, training and motivational techniques; communication channels, tools, techniques and methods; configuration management; conflict resolution; customer satisfaction metrics; data-gathering techniques; decision-making; delegation techniques; diversity and cultural sensitivity; emotional intelligence; expert judgment technique; facilitation; generational sensitivity and diversity; information management tools, techniques and methods; interpersonal skills; knowledge management; leadership tools, techniques and skills; lessons learned; management techniques; meeting management techniques; negotiating and influencing techniques and skills; organizational and operational awareness; peer-review processes; presentation tools and techniques; prioritization/time management; problem-solving tools and techniques; project finance principles; quality assurance and control techniques; relationship management; risk assessment techniques; situational awareness; stakeholder management techniques; team-building techniques; and virtual/remote team management.

Conclusion

I hope this has given you a better understanding of the PMP domains and what they cover. Future article topics will be focusing on the each of the PMP domains and going into more details about their respective tasks, knowledge and skills.

Sources

Project Management Professional (PMP)®️ Handbook, PMI

Project Management Professional (PMP)®️ Examination Content Outline, PMI

 

To download Free Project Management Templates you can visit www.managementproject.net

Supermarket project– multibodegas

Supermarket project – multibodegas

 

Project Name: Supermarket project– multibodegas

Description: The content is building a Maxibodega has architecture; cuts; elevation; plane structures, section beams, slab lightened; columns section and distribution; details miscellaneous metal frame plane with respective joists and details armed

Category: Autocad Drawing / Projects / Store houses – ware houses

File extension: DWG

Download Link

Recreation center tour

Recreation center tour

Project Name: Recreation center tour

Description: Recreation Center Tour – Project – Plants – cuts

Category: Autocad Drawing / Projects / Tourism – recreation

File extension: DWG

 

Download Link

Ways to Increase Your Salary as a Project Management Professional

Ways to Increase Your Salary as a Project Management Professional

 

Top performing companies successfully complete 89 percent of their projects, meaning effective project managers not only impact the success of their company’s top initiatives—they enable better project performance overall.

Ninety-seven percent of organizations strongly agree that project management is critical to the success of their company, according to a survey by Pricewaterhouse Coopers. From seeing complex projects from inception to completion, project managers have the capacity to reduce company costs, increase organizational efficiency, and help generate higher revenue.

When it comes to project management, salaries can be rewarding, but also depend on several factors. Let’s take a deeper dive into how certifications, earning an advanced degree, specialization, and other factors can add more money to your paycheck.

Certification and Graduate Degrees

Those with a PMP certification earn 20 percent more than those without one. The median salary for project managers holding this certification is $111,000, versus a median salary for non-PMP holders at $91,000 across all industries.

The PMP certification demonstrates your proficiency in becoming a certified project manager. Earning one not only helps you enhance your salary, it demonstrates to employers that you have the skills, knowledge, and organization to successfully manage projects and teams. PMP certification is often preferred or recognized for promotions and career advancement.

The certification is earned through the Project Management Institute, a globally-recognized association that promotes collaboration, education, and research within project management. The organization also maintains international certification standards, credentialing, policies, and procedures.

In addition to certification, 34 percent of project management job postings prefer or require a graduate degree, according to a report from Burning Glass Labor Insight. A master’s degree in project management can equip you with the concrete skills you need to lead complex projects.

Specialization

Along with earning your PMP certification, you can further increase your salary depending on your specialization within project management. For example, you may choose to become a program manager or a portfolio manager.

Here’s how the three break down:

  • Project managers plan, direct, and close projects by determining responsibilities, creating an inclusive plan, and managing the budget. They typically make an average salary of $108,200.
  • Program managers execute several related projects in a collective way—also known as a program—to improve a company’s outcomes, and they command a median salary of $120,000.
  • Portfolio managers analyze an organization’s projects to help companies identify the best tasks, distribute the right resources, and improve project performance. They earn a median salary of $128,000.

Project Team Size

Team size also affects a project manager’s income. Depending on the size of the team, a project manager could earn an additional $20,000 per year in salary. According to the Project Management Institute, ranges include:

  • One to four people: $100,000
  • Five to nine people: $107,070
  • 10 to 14 people: $111,000
  • 15 to 19 people: $115,823
  • 20 or more people: $120,000

Project managers also make 40 percent more if they are managing ventures that surpass $10 million.

Industry

Your chosen industry can have a significant impact on your earnings as a project manager. According to the Project Management Institute, project managers in the following industries report the highest median income in the nation:

  • Pharmaceuticals: $125,500
  • Agriculture, Mining, and Natural Resources: $120,640
  • Consulting: $120,000
  • Aerospace: $115,000
  • Engineering: $112,000
  • Information Technology: $110,000
  • Oil and Gas: $110,425
  • Government: $110,000

Project management salaries within the science, technology, engineering, and math (STEM) fields are rewarding due to the rapid growth and high salaries within the field. In fact, 93 percent of STEM jobs offer wages well above the national average, and the national median salary for all STEM positions is almost double the average wage for non-STEM roles.

Within the government, projects are more complex than other fields and often require specialized knowledge of particular software, making project management salaries higher than average.

Location

Where you choose to work can also affect your salary. This includes locations both within the U.S. and worldwide.

You can make up to $16,000 more depending on your location within the U.S.

Nationwide, project manager salaries are:

  • Miami: $83,615
  • Austin: $87,742
  • Chicago: $89,065
  • Boston: $91,440
  • Charlotte: $93,320
  • Houston: $93,927
  • Seattle: $94,841
  • New York City: $95,855
  • San Francisco: $99,748
  • Silicon Valley: $110,197

Keep in mind that cost of living varies with each city. For example, the cost of living in Seattle is 24 percent more expensive than the average city, while the cost of living in Austin is three percent lower.

In addition to the U.S., project managers earn the most in countries such as Australia, Switzerland, the Netherlands, Germany, and Canada. According to ProjectManager.com, they command a median salary of:

  • Canada: $95,140
  • Australia: $134,658
  • Switzerland: $133,605
  • The Netherlands: $103,274
  • Germany: $101,983

Where you choose to work can have a huge impact on earnings, in addition to certification and advanced degrees, specialization, project team size, and industry. Project managers should then consider a multitude of factors when looking at salary.

 

Source: www.northeastern.edu

Types of structural supports – Boundary Conditions

Types of structural supports – Boundary Conditions

 

Types of supports

Defining the boundary conditions in a model is one of the most important part of preparing an analysis model, irrespective of the software that you use. Supports are an essential part of building your model to ensure accurate and expected results.

These are not to be ignored nor guessed as it can lead to your structure not behaving in the way you anticipated. To define supports you need to be aware about the support detailing in case of steel structures. For example, a support column in a steel structure can be pinned or fixed, depending upon the detailing adopted.

1. Fixed support:

This is the most rigid type of connection. It restrains the member in all translations and rotations, which means it can’t move or rotate in any direction. The best example of this is a column placed in concrete which can’t twist, rotate or displace. A fixed support in three dimensional model will have 6 degrees of freedom restrained, which are three translations and three rotations in three orthogonal directions, X, Y and Z.

These are beneficial when you can only use a single support. The fixed support provides all constrains necessary to ensure the structure is static. It’s the only support which is used for stable cantilevers.

The greatest advantage provided by this support can also lead to its downfall as sometimes the structure requires a little deflection or some play to protect the surrounding materials. For example, as concrete continues to gain strength, it also expands. Hence it’s crucial that the support is designed correctly else the expansion could lead to reduction in durability.

Fixed support reactions

Beam fixed on the wall as an example

2. Roller support:

This support can’t resist the horizontal support but can resist the vertical support. This connection is free to move in horizontal direction as there is nothing restraining it.

The most common use of this support is in a bridge. Typically a bridge consists of a  roller support at one end to account for the vertical displacement and expansion from changes in temperature. It’s required to prevent the expansion causing damage to a pinned support.

The roller support doesn’t resist horizontal force which acts as its limit as the structure will require another support to resist the horizontal force.

For a structure to be stable roller support is used along with pin support.

 

Roller support reactions

Roller support on one end of a bridge

3. Pinned support:

A pinned support is a common type of support in civil engineering. Like hinge, this support allows rotation to occur but not translation which means that it resists the horizontal and vertical forces but not a moment.

Pinned supports are widely used in trusses.  By joining multiple members by pinned connections, the members push against each other which will induce an axial force within the member. The advantage of this support is that the members won’t have internal moment forces, and can be designed only according to their axial force.

The pinned support can’t completely resist a structure on its own as you need at least two supports to resist the moment coming on the structure.

Hinge support reactions

Hinge support in sydney harbor bridge

4. Internal Hinge

 Interior hinges are often used to join flexural members at points other than supports. In some cases, it is employed deliberately so that the excess load breaks the weak zone rather than damaging other structural elements.

Permeability of Soil: Definition, Darcy’s Law and Tests

Permeability of Soil: Definition, Darcy’s Law and Tests

 

Definition of Permeability:

It is defined as the property of a porous material which permits the passage or seepage of water (or other fluids) through its interconnecting voids.

A material having continuous voids is called permeable. Gravels are highly permeable while stiff clay is the least permeable, and hence such a clay may be termed impermeable for all practical purpose.

The study of seepage of water through soil is important for the following engineering problems:

1. Determination of rate of settlement of a saturated compressible soil layer.

2. Calculation of seepage through the body of earth dams and stability of slopes for highways.

3. Calculation of uplift pressure under hydraulic structure and their safety against piping.

4. Groundwater flow towards well and drainage of soil.

Darcy’s Law (1856) of Permeability:

For laminar flow conditions in a saturated soil, the rate of the discharge per unit time is proportional to the hydraulic gradient.

q = kiA

v = q/A = Ki … (7.1)

Where q = discharge per unit time

A = total cross-sectional area of soil mass, perpendicular to the direction of flow

i = hydraulic gradient

k = Darcy’s coefficient of permeability

v = velocity of flow or average discharge velocity

If a soil sample of length L and cross-sectional area A, is subjected to differential head of water h1 – h2, the hydraulic gradient i will be equal to [(h1 – h2)/L] and we have q = k. [(h1 – h2)/L].A.

When hydraulic gradient is unity, k is equal to V. Thus, the coefficient of permeability, or simply permeability is defined as the average velocity of flow that will occur through the total cross-sectional area of soil under unit hydraulic gradient. Dimensions are same as of velocity, cm/sec.

The coefficient of permeability depends on the particle size and various other factors. Some typical values of coefficient of permeability of different soils are given in Table 7.1.

Discharge Velocity and Seepage Velocity:

The total cross-sectional area of the soil mass is composed of sectional area of solids and voids, and since flow cannot occur through the sectional areas of solids, the velocity of flow is merely an imaginary or superficial velocity.

The true and actual velocity with which water percolates through a soil is called the velocity of percolation or seepage velocity. It is the rate of discharge of percolating water per unit of net sectional area of voids perpendicular to the direction of flow.

Validity of Darcy’s Law:

In accordance with the Darcy’s Law, the velocity of flow through soil mass is directly proportion to the hydraulic gradient for laminar flow condition only. It is expected that the flow to be always laminar in case of fine-grained soil deposits because of low permeability and hence low velocity of flow.

However, in case of sands and gravels flow will be laminar upto a certain value of velocity for each deposit and investigations have been carried out to find a limit for application of Darcy’s law.

According to researchers, flow through sands will be laminar and Darcy’s law is valid so long as Reynolds number expressed in the form is less than or equal to unity as shown below –

Where v = velocity of flow in cm/sec

Da = size of particles (average) in cm.

It is found that the limiting value of Reynolds number taken as 1 is very approximate as its actual value can have wide variation depending partly on the characteristic size of particles used in the equation.

Factors affecting permeability are:

1. Grain size

2. Properties of pore fluid

3. Void ratio of the soil

4. Structural arrangement of the soil particle

5. Entrapped air and foreign matter

6. Adsorbed water in clayey soil

4. Effect of degree of saturation and other foreign matter

k will decrease if air is entrapped in the voids thus reducing its degree of saturation. Percolating water in the field may have some gas content, it may appear more realistic to use the actual field water for testing in the laboratory.

Organic foreign matter also has tendency to move towards critical flow channels and choke them up, thus decreasing permeability.

5. Effect of adsorbed water – The adsorbed water surrounding the fine soil particle is not free to move, and reduces the effective pore space available for the passage of water.

Capillarity-Permeability Test:

The set-up for the test essentially consists of a transparent tube about 40 mm in diameter and 0.35 m to 0.5 m long in which dry soil sample is placed at desired density and water is allowed to flow from one end under a constant head, and the other end is exposed to atmosphere through air vent.

At any time interval t, after the commencement of the test, Let the capillary water travel through a distance x, from point P to Q. At point P, there is a pressure deficiency (i.e., a negative head) equal to hc of water.

If the coefficient of permeability is designated as ku at a partial saturation S, the above expression can be rewritten as –

In order to find the two unknowns k and hc in the above equation, the first set of observations are taken under a head h1. As the capillary saturation progresses the values of x are recorded at different time intervals t.

The values of x2 are plotted against corresponding time intervals t to obtain a straight line whose slope, say m, gives the value of [(x22 – x21)/(t2 – t1)] . The second set of observation are taken under an increased head h2 and values of x2 plotted against corresponding values of t to obtain another straight line, whose slope m2 will give the value [(x22 – x21)/(t2 – t1)].

By substitution in Eqn. 7.1, we obtain the following two equations, which are solved simultaneously to get k and hc.

The porosity n required in the above equation is computed from the known dry weight of soil, its volume and specific gravity of soil particles.

Permeability of Stratified Soil Deposits:

In general, natural soil deposits are stratified. Each layer may be homogeneous and isotropic. When we consider flow through the entire deposit the average permeability of deposit will vary with the direction of flow relative to the bedding plane. The average permeability for flow in horizontal and vertical directions can be readily computed.

Average Permeability Parallel to Bedding Plane:

Figure 7.9 shows several layers of soil with horizontal stratification. Let Z1, Z2, ….Zn be the thickness of layers with permeabilities k1, k2, … kn.

For flow parallel to bedding plane the hydraulic gradient i will be same for all layers. The total discharge through the deposit will be the sum of discharges through individual layers.

Average Permeability Perpendicular to Bedding Plane:

For flow in the vertical direction for the soil layers shown in Fig. 7.10.

In this case the velocity of flow, v will be same for all layers the total head loss will be sum of head losses in individual layers.

h = h1 + h2 + h3 + … + hn (i)

If kz denotes average permeability perpendicular to bedding plane, applying Darcy’s law, we have –

How to Test Compaction of Soil?

How to Test Compaction of Soil?

 

Compaction test is conducted in the laboratory to determine the relation between the dry density and the water content of the given soil compacted with standard compaction energy and to determine the OMC corresponding to the MDD.

The OMC obtained from the laboratory compaction test will help in deciding the amount of water to be used for compaction in the field. The MDD obtained from the laboratory compaction test helps in knowing the dry density achievable in the field compaction and also as a check for quality control.

Based on the compacted energy used in compacting the soil in the laboratory test, the laboratory compaction tests are of two types:

1. Standard Proctor test.

2. Modified Proctor test.

 

1. Standard Proctor Test:

In this test, the soil is compacted in three layers, each layer subjected to blows of a rammer with falling weight of 5.5 pounds (2.6 kgf) falling through a height of 12 in. in a cylindrical mold of internal diameter of 4 in. and effective height of 4.6 in.

The compaction parameters in a standard Proctor test are – W is the weight of rammer blow = 5.5 pounds, h is the height of fall = 12 in. = 1 ft, n is the number of blows per layer = 25, l is the number of layers = 3, and Vm is the volume of the mold = 1/30 cubic ft. The total compaction energy imparted on the soil per unit volume in this test is –

IS – 2720 (Part 7) – 1980 recommends the Indian Standard light compaction method based on standard Proctor test in metric system. The standard Proctor test or IS light compaction can be used as a criteria for the compaction of subgrades on highways and earth dams, where light rollers are used.

 

2. Modified Proctor Test:

 

Advances in construction technology resulted in the development of heavier rollers, which impart higher compaction energy during field compaction. To provide a laboratory control criterion for the higher compaction energy, the modified Proctor test was developed and standardized by the American Association of State Highway (and Transportation) Officials (AASHO or AASHTO) and by US Army Corps of Engineers for airfield construction.

In modified Proctor test, the soil is compacted in the same mold as in standard Proctor test, which has internal diameter of 4 in. and affective height of 4.6 in. giving a total internal volume of 57.805 cubic in. or 1/30 cubic ft. The rammer is bigger with a hammer of weight 10 pounds (4.5 kgf) falling through a height of 18 in. The soil is compacted in five layers, each layer being given 25 blows.

The compaction parameters in modified Proctor test are as follows – W is the weight of hammer blow = 10 pounds, h is the height of fall = 18 in. = 1.5 ft, n is the number of blows per layer = 25,l is the number of layers = 5, and Vm is the volume of the mold = 1/30 cubic ft.

The compaction energy imparted to the soil, per unit volume, in the modified Proctor test is:

Thus, the compaction energy in the modified Proctor test is (56250/12375) 4.55 times that in standard Proctor test.

If the soil fraction retained on 20 mm sieve is more than 5%, a bigger mold of 5.9 in. (15 cm) internal diameter and 5 in. (12.73 cm) internal height giving a total volume of 137.04 cubic in. or 1/12.611 cubic ft (2250 cm3) is used. When the bigger mold is used, the soil is compacted with 56 blows for each layer.

IS 2720 (Part VII) 1980 and Part VIII-1983 have recommended procedures corresponding to these two tests as follows:

1. IS light compaction test.

2. IS heavy compaction test.

1. IS Light Compaction Test:

The objective of the IS light compaction test is to determine the relation between the water content and the dry density of compacted soil and to determine the MDD and OMC from this test. The compaction energy used to compact the soil corresponds to that of standard Proctor test.

The compaction parameters in IS light compaction test are as follows – W is the weight of hammer blow = 2.6 kgf, h is the height of fall = 31 cm, n is the number of blows per layer = 25, and I is the number of layers = 3, and Vm is the volume of the mold = 1000 cubic centimeter (cc). The total compaction energy imparted on the soil in this test is –

E = Whnl = 2.6 × 31 × 25 × 3 = 6045 kgf cm

The total compaction energy imparted on the soil per unit volume in this test is –

E = 6045/1000 = 6.045 kgf cm/cm3

2. IS Heavy Compaction Test:

The IS heavy compaction test is similar to IS light compaction text except for the following differences:

1. A heavy rammer of 4.9 kgf falling weight that falls through a height of 45 cm is used for compacting the soil in IS heavy compaction.

2. The soil is compacted in five layers of equal thickness in the compaction mold.

3. The initial water content to be used in the first trial is 3%-5% for sandy and gravelly soils and 12%-16% below plastic limit for cohesive soils.

To increase the accuracy of the test results, it is desirable to reduce the increment of water in the region of OMC.

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