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Construction formwork and scaffolding design

15/12/2015

Formwork or forms are used to retain concrete in place until it gains sufficient strength to support itself. Concrete walls and columns require formwork. Elevated concrete slabs require forms and support work to hold the concrete while it gains strength. The edges of slabs and beams require forms. Often to reach elevated areas contractors construct access scaffolding. In fact formwork and scaffolding are an integral part of many construction projects.

Formwork and support work should be designed to ensure it will be strong enough to withstand and carry the weight of wet concrete, reinforcing, cast-in items, and the people and equipment used to place the concrete. The design normally assumes a rate of pour, and if this rate is exceeded it could lead to overloading of the formwork. Also materials should not be heaped on formwork, or scaffolding, since this could result in the equipment carrying a load it was not designed for.

Case study:
I was the Project Director on a project that involved constructing a reinforced concrete slab, two metres thick, and eight metres above an operational railway line which the supporting scaffold had to span. The support-work was designed by our Formwork Design Engineer, who also produced detailed drawings of how the support-work should be constructed. The quantity of equipment was ordered from these drawings.

There was a full-time Project Manager allocated to the project, and at the time, I was responsible for five other projects, situated hundreds of kilometres apart, so I visited the project approximately every two weeks. The day before the concrete slab was due to be poured I visited another project, and at the last minute decided to make a detour on my homeward journey to check the slab was ready for the concrete.

On arriving on the project site I was informed the slab was ready to receive concrete, however, I noticed a number of steel beams that had been ordered were lying unused on the ground. I queried this, and was informed the Supervisor had decided the beams were superfluous and omitted them. I contacted the Formwork Design Engineer, and explained my concerns. He immediately checked his calculations, and called me back to say he had major concerns, and was on his way to the site – some 200 kilometres from his office.

When our Engineer arrived and inspected the support-work, he found the omission of the support beams meant the load of the wet concrete on the slab would not have been distributed evenly, and would have resulted in some of the scaffold support legs carrying double their load capacities. To compound the error, the Engineer found a mistake with his original calculations, which would have anyway resulted in the legs carrying an extra 20% over their capacity. This additional 20%, together with the doubling of the load, would have resulted in some scaffold legs carrying nearly two and a half times the load they were capable of carrying.

If we had gone ahead with placing the concrete on the slab there is no doubt the support-work would have failed with catastrophic results, people would probably have been killed and others seriously injured, the railway would have been closed for weeks, the project would have been delayed by months, and there would have been costly property damage.

As a result we postponed the concrete pour until we were able to install additional support-work to carry the load, ensuring none of the scaffold was over-loaded.

There are several lessons from the above:

the formwork design must be double-checked to ensure there are no errors or erroneous assumptions
the design drawings should be followed and Supervisors should not omit items, no matter how unnecessary they may seem, unless they first check with the Designer
it’s important to check that the support-work and formwork has been erected according to the design drawings. These checks should also include:
1. ensuring all bracing is installed
2. all support-work is erected straight, vertical and level
3. the equipment is in good condition
4. the supporting ground is firm and capable of carrying the load
5. the support-work and formwork is all tightened and secured properly
6. remembering that support-work erected on top of existing elevated slabs transfer the load on to these slabs, so they must be designed, and supported in such a way that they can carry this load

Conclusion

Formwork that is not designed and installed correctly can result in accidents, poor quality, lost time, and even serious injury and death. Construction project managers and supervisors must ensure that formwork and access scaffolding is not damaged, which results in additional costs, and can also weaken the equipment. Never take a chance or shortcuts when installing formwork and access scaffold.

Using the correct formwork installed with qualified and trained people will improve productivity and quality, while ensuring that the construction work is done safely.
#constructionmanagement #formwork #scaffolding

Do you want to learn how to manage construction projects successfully

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'Successful Construction Project Management: The Practical Guide'
'Building a Successful Construction Company: The Practical Guide'
'Construction Book reviews'
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© 2022 This article is not to be reproduced for commercial purposes without written permission from the author.

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Is your construction project working through the holidays?

11/12/2015

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Image courtesy of photoexplorer at FreeDigitalPhotos.net

In some countries the construction industry closes over the Christmas and New Year holidays. Last week I published an article ‘is your project holiday ready?’ Judging by comments some projects will be working through the holidays. I’ve often worked an extra week into the holidays, always with limited results. Some clients are eager to push their contractors to work on holidays but don’t realise the implications.
In some countries holidays may not be celebrated now, but later in the year. Whenever you may have a holiday period you will almost definitely face challenges getting your project to continue working through the holidays.

Why it is not good when construction projects work through the holidays

Here are a few reasons why I don’t like working through holiday periods.

Our employees are usually tired after working through the year and are looking forward to their holiday break and an opportunity to rest. They deserve a break.
Our employees have a right to spend time at home with their family. Official holidays and festivities are often a time for the family to be together – some family members travel great distances to be with their family at these times.
Employees forced to work over these holidays often face an unhappy family which causes tension, poor morale and employee unhappiness. There is a saying a happy wife means happy life. Certainly a happy family is definitely a happy life.
Productivity is low in these times as workers are thinking of others on holiday and generally have low morale.
Safety is impacted due to workers not concentrating on their work.
We normally have to pay overtime rates to our employees, which costs more money – normally money not budgeted in the project price.
High absenteeism over this period may mean a critical worker such as a crane operator is absent which can have a snowball effect on a team’s productivity.
Some suppliers and subcontractors may be closed which will impact work than can be done.

If your construction project must work through the holidays be prepared

If you absolutely have to work the project through the holidays then consider the following:

Ensure you have the client’s or owner's permission to work.
Check that the project won’t impact neighbours or break local noise prohibitions on the holiday.
Ensure that key people will be available – there’s nothing worse than having 90% of your team arrive at work, but the crane operator or excavator operator aren’t available so operations cannot continue as normal and time is wasted.
Check that there will be sufficient supervision on the project. I’ve found that often workers are on site but aren’t supervised properly because senior staff aren’t at work, or are sitting chatting in the office. If anything arrange extra supervision.
Over festivals and holidays workers may be more inclined to consume alcohol or take drugs so ensure alcohol and drug testing procedures are in place and zero tolerance is enforced. Drugs and alcohol impair judgement and negatively impact productivity.
Ensure that the project has sufficient materials for the work that has to be done, or make arrangements for suppliers to stay open.
Often Head Office may close over these periods, so it may be necessary to make additional arrangements to ensure your hourly and weekly wage earners will receive pay for this period.
Ensure that support staff are available – these may include mechanics, safety officers, quality and testing people, etc.
Try and set specific targets that must be completed in this time. Teams with specific goals are often more focused.
Make arrangement for the workers who worked over the holiday time to have time off at a later date. Everyone deserves a rest.
Ensure subcontractors who are required are committed to working over this period. Again it could be disappointing if, say, your teams were all at work but the reinforcing or scaffolding contractors weren’t available. There would probably be little progress you could make.

Conclusion

Working over the holidays is often counterproductive, costs money and often achieves little. However, if you have to work it is best to be prepared so that you maximise productivity and aren’t adversely impacted by factors that could have been avoided if proper planning was done before hand.
Don’t let working through holidays become a habit or a norm. Plan your projects to take holidays into account.
Happy holidays.

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#constructionmanagement #constructionprojectmanagement #contractors
© 2015 This article is not to be reproduced for commercial purposes without written permission from the author.

Other useful articles
Don't let overtime on your construction project eat your PROFITS
after the holidays - what will happen on your construction project?
Why is there poor productivity on your construction project?

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Is your construction project holiday ready?

7/12/2015

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Image courtesy of arztsamui at FreeDigitalPhotos.net

It’s that time of the year again. All too soon we have reached the end of another year. Many contractors close down over the holidays and staff will be eagerly anticipating their own holidays. Time to spend with their families. Time to get away from work. Hopefully time to rest, relax and recuperate after a year of hard work.
As the holidays approach construction project managers and the rest of the team start focusing on their own holidays. This includes arrangements for their vacations including booking accommodation and flights and preparing for the festivities.

But is your construction project site ready for the holidays?

Preparing Your Construction Project For The Holidays

What you need to do
Usually preparing the construction project for the holidays should start several weeks before the start of the holidays. These preparations could comprise ensuring:

that critical tasks are completed in accordance with the project schedule or program (these may include for instance; closing up buildings to make them weather tight, pouring concrete to allow curing time over the holidays so that the forms can be removed immediately when work resumes, or completing sections of roads so they can be opened in time for the holidays meaning that detours and deviations don’t have to be maintained over the holiday period – delays on some activities may mean they are done only after the holiday period which could result in significant delays and extra costs)
invoices for completed work or monthly valuations have been submitted – this may include making prior arrangements with the client for an earlier submission so that payments can be made, and ensuring that payments can be received in your absence
subcontractors’ and suppliers’ invoices are paid – remember they have bills to pay over the holidays (ensure they submit their invoices timeously before the holidays so that payments can be prepared before the holidays)
arrangements have been made to pay your staff and workers
utility bills have been paid – you don’t want to return to the project only to find that the power or water services have been terminated
if required, security services are in place for the project site over the holiday period
loose materials are secured in case of severe weather over the holidays
equipment is parked in secure areas – including being removed from areas that may be flooded
storm-water drains are clear so that unexpected storms don’t flood the site
workers and staff are aware of when the project will close and when work will resume
for remote projects, transport is arranged to take workers home at the start of the holidays and return them to the project site – including ensuring workers are aware of these arrangements and times
the client is aware of when the construction site will be closed
suppliers are informed when the project is closed so that deliveries don’t happen over the holidays
arrangements are in place to keep essential operations running during this time – such as maintaining pumps removing water from the works or teams maintaining traffic signage and barricades
the construction site is barricaded and secure so that unauthorised people can’t enter, possibly injuring themselves, or vandalising and stealing property
project personnel are contactable and available in case of an emergency during this time
check that suppliers will be open when you return to work after the holidays – some suppliers may return some days after your project reopens so you may have to arrange for deliveries to happen before you close so you have sufficient materials in stock until normal deliveries can resume
where deliveries are required in the first few days after the holidays thesedeliveries should be arranged now for your return so they are already booked in
communicate with subcontractors ensuring they understand when the project site will shut and reopen and that they know the critical tasks that need to be completed before the holidays
Have a check list of everything that needs to be done by the project close and ensure everyone knows what has to be done – when the end of shift comes on that last day you may be left alone to shut the project down as everyone rushes to get ahead of the holiday traffic

Not Preparing Your Construction Project Could Spoil Your Holiday

Adequate preparation should mean you can return to the project after the holidays without having to face a crisis immediately on your return.
Happy holidays.

Like this article – please comment, like and share it.

To read more about the author’s books and find out where you can purchase them visit the pages on this website by clicking the links below:
'Successful Construction Project Management: The Practical Guide'
'Building a Successful Construction Company: The Practical Guide'
'Construction Book reviews'
To read more about the author visit the page 'Paul Netscher'
Want to contact Paul Netscher please enter your details on 'Contacts'
Find out how Paul Netscher can help you by visiting Construction Management Services

Order your books from Amazon
Order your books from Amazon UK

© 2015 This article is not to be reproduced for commercial purposes without written permission from the author.

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Mistakes that impact construction schedules/programmes – part 2

3/12/2015

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Picture courtesy of Joao Neto

In a previous article I discussed 10 mistakes that occur in construction schedules or programmes. (Read part 1) These mistakes could mean that the contractor is working to a schedule that is incorrect or unworkable and the project is likely to be completed late.
Here are a few more common errors to avoid:

Making the program fit the client’s contractual dates without considering if it’s possible or how you will make it happen. Some contractors are eager to please the client or owner and will agree to contractual completion dates that are impossible. Careful planning needs to be done to see how the schedule can be made to fit the completion dates. If the dates are impossible the client needs to be advised. Sometimes it may be possible to give the client partial completions and access which may be sufficient for the client to continue their work.
Not allowing for statutory holidays. These holidays can impact the project as workers usually have to be paid additional rates, and some services and suppliers may not be available during these times. Sometimes it is also more than the time lost directly because of the holidays – sometimes projects close a half day earlier the day before holidays, or in some areas there could be a tardy return of all workers which impacts production immediately after the holiday.
Not considering the ground conditions. Excavating in rock can be a slow and difficult process and take much longer than excavating in soft material.
Not getting the client to agree and accept the schedule in writing. The accepted contract schedule/programme will form the basis of delay and acceleration claims. Many clients delay accepting the schedule as it gives them time to issue drawings and get their ‘house in order’ before the contractor is able to lodge their claim
The schedule doesn’t take into account the methodology of construction.
No thought is given to the availability of materials or their rate of delivery.
Safety isn’t considered. This is particularly a concern when cranes have to operate in close proximity to each other, or loads are lifted over working areas and where workers are working above work areas below.
The movement of materials and equipment aren’t considered. Large heavy items may need to be installed before buildings can be closed-up and completed. The movement and handling of materials often causes bottlenecks with production – particularly with high-rise projects, congested sites or projects that are in difficult mountainous terrain such as power transmission lines, bridges, railway tracks, etc.
The scheduler or planner accepts the first schedule they produce. It’s sometimes possible by varying sequencing to change the critical path items. By starting the project elsewhere or tackling it simultaneously from different points it may be possible to shorten the overall project duration. Small changes to a schedule can sometimes make significant changes to the project duration.
The schedule allocates too many activities or trades to happen in an area at the same time. For instance it’s difficult and unproductive to have other trades working in a room where floor tiles are being laid.

Conclusion
The scheduler or planner should be experienced in preparing construction schedules. The project manager should ensure that the schedule takes into account the conditions on the project site, the available resources and the chosen methodologies. Where necessary the key subcontractors should be consulted to ensure that time allocated to their tasks is sufficient.
Preparing the best workable schedule is an art, a science and one that needs expertise and experience.
But of course even a good schedule is worthless if it’s not followed or isn’t updated correctly. But this is a discussion on its own which we will discuss in 2016.

What mistakes and pitfalls have you experienced with project schedules?

To read more about the author’s books and find out where you can purchase them visit the pages on this website by clicking the links below:
'Successful Construction Project Management: The Practical Guide'
'Building a Successful Construction Company: The Practical Guide'
'Construction Book reviews'
To read more about the author visit the page 'Paul Netscher'
Want to contact Paul Netscher please enter your details on 'Contacts'
Find out how Paul Netscher can help you at construction management services

Order your books from Amazon
Order your books from Amazon UK

© 2015 This article is not to be reproduced for commercial purposes without written permission from the author.

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Construction formwork and scaffolding design

Conclusion

Do you want to learn how to manage construction projects successfully

Is your construction project working through the holidays?

Why it is not good when construction projects work through the holidays

If your construction project must work through the holidays be prepared

Do you want to learn how to manage construction projects successfully

Is your construction project holiday ready?

Preparing Your Construction Project For The Holidays

Not Preparing Your Construction Project Could Spoil Your Holiday

Mistakes that impact construction schedules/programmes – part 2

Archives

Categories

Construction Books

Construction services

Construction formwork and scaffolding design

Conclusion

Do you want to learn how to manage construction projects successfully

Is your construction project working through the holidays?

Why it is not good when construction projects work through the holidays

If your construction project must work through the holidays be prepared

Do you want to learn how to manage construction projects successfully

Is your construction project holiday ready?

Preparing Your Construction Project For The Holidays

Not Preparing Your Construction Project Could Spoil Your Holiday

Mistakes that impact construction schedules/programmes – part 2﻿

Archives

Categories

Construction Books

Construction services

Mistakes that impact construction schedules/programmes – part 2