Hollow Block Wall 4

Are you referring to a partially reinforced (old term) wall with some vertical cores grouted and with a bond beams (possibly intermediate)?

What is your structural standard that the wall must meet?

What is the purpose and application of the wall?

Is the wall coated?

If you are talking about flexure, I have used an air bag test, but this is a destructive test usually done in a laboratory. Any on-site testing would be be affected by fixity and wall tickness/width/height ratios. Also, there would be the effects of the vertical loads on the wall at the time.

There is no standard for the "porosity" of a normal masonry wall. There are no common standards for the "porosity" of the the units (ASTM C90 would apply). The mortar selection is dependant on the specifier (ASTM 270). There are water column tests that have been used to test the effectiveness of coatings. One of the factors in the performance of an in place wall is the workmanship.

You could use some sort of a test (usually laboratory) to determine the performance of someting like wind driven rain.

Dick

I soldered up a frame with some misting nozzles and added a flow meter to a garden hose hookup so an engr. could hang this in front of windows and check their watertightness at a certain flow. Must be something like that for block. But the coating would have to be cheaper than the test unless it's a big wall.
I don't think a plate test is what is required. A small scale loading would not tell much.

Window testing is normally a ;aboratory product test.

There are accepted laboratory test procedures for windows. They require close monitorings of flow rates and the pressure to test the window. This is usually a certification or a product acceptance test.

There are also field test methods for the installed performance of a window that really involve a short term drenching the window and partial wall assembly. These are designed to test the installed properties of a window in place.

You could run a similar short term test for a masonry wall, but you may not determine much without specific criteria. To properly test a wall ASSEMBLY for water penetration you will need duration and a pressure differential. Water penetration of a wall assembly is a combination of the materials (masonry units), mortar, construction procedure, performance of coatings and internal waterproofing methods (if any).

Are you just after the "porosity" of a wall or the "integrity" of a wall without a standard to meet?

It sounds like you have been commissioned to cary out a verification without any guidelines or criteria to meet.

Dick

Zambo,

Concretemasonry is right, some more information is required.

I also have some questions for you.

1. Has the wall already been built?

2. What type of masonry wall is it....freeway sound barrier wall, shear-bearing wall in building...?

3. Do you know the purpose of the tests...evaluation of out of plane load capacity, sound trasnmission etc? The list of tests required to evaluate stuctural integrity can be quite numerous, therefore, it is prudent to narrow the scope to deal with what you are attempting to evaluate.

4. Are the tests meant to be insitu, lab, or both?

5. What codes and standards govern....european, american..?

Thank you to all for the responses.

The walls (several and a large area) have been built and now the consultant would like to prove they are not acceptable. As the walls are acceptable and properly carried out I have little other option than to prove the integrity both for strength and porosity.

I have previously carried out an integrity test on a parapet where we calculated the required horizontal load capacity and then applied the force with a jack. If I knew a standard (British Standard would be applicable) that gave me a horizontal force then I would apply it.

For the porosity test I gather that applying a coating may be easier than the test. Who can recommend a coating (preferably clear that can be applied on the existing paint) that would protect the wall against driven rain?

You have to be a little more specific if you can. It is difficult to give an answer without a feeling for the problem. Knowing what the problem or points of concern are would help give some direction to your efforts. Is it just a leaky wall?

Doesn't the consultant have to show in what way they are not acceptable?

Words like integrity, strength and posity are too general. So far, I have assumed you are looking at the existing structure since the products and assemblies chosen by the designer are apparently carried out properly. This apparently would involve on site testing or documentation.

What type of strength are you concerned with? - Wall compressive, flexural, or shear strength? With a masonry wall you have to deal with an assembly. What is the specific composition of the wall and the materials used/specified? What is the purpose of the wall - structural?, privacy?, fire barrier?, sound barrier? liquid constainement? blast barrier?

Regarding the "porosity", what is the problem and when does it occur? Are there any openings and where are the horizontal bond beams? What are the interior and exterior finishes? Was any water proofing coating applied? Was any effort made to provide flashing internally or at other locations for moisture control?

You mention British standards. Is this built using traditional British materials and practices or would other standards be applicable?

Some information is required to make a recommendation.

concretemasonary

the consultant is asking us to prove the integrity. I don't believe asking him to clarify will provide any more details. Let's assume he will be satisfied if I prove the shear strength, the wall is connected to the floor slab with dowels at every vertical stiffener (4m centres) and fexural strength. The walls are not load bearing and therefore I do not think we need to prove the compressive strength. I believe I can prove both of these by applying a horizontal force but I do not have a specification for that force.

The purpose of the walls are internal partitions and external walls. The construction of both is the same. The walls are 6m high with vertical stiffener infills and horizontal bond beam infills.

No coating is applied except for exterior quality paint.

No efforts have been made with flashings for moisture control. The external blockwork walls stand on the edge of the concrete slab.

The walls have been constructed in Thailand but British or Australian standards can be used.

Maybe the question should be:

What part of the contract documents does the wall construction contravene? Is the testing in accordance with the contract documents? Who is responsible for quality assurance/control?
What tests were undertaken?

Dik

So British or Australian standards can be used...

I believe these documents contain design provisions and standard specs: British---BS 5628 Australian---AS CA47

The link for the British Standards Institute is you can do a search

For masonry testing that goes beyond the scope of BS 5628, start with the link below

If you are dealing with a building control agency (building dept), the term "integrity" may involve more than just structural concerns.

By the way, is there any evidence that the construction was inspected by an approved individual? This is important as it will provide some evidence that the construction complies with the plans.

Henri2

thanks for your post. I would be plesed to buy the British or Australian standards but I'm worried that I buy then when delivered in say 14 days time they don't give an answer.

Although there have been a few suggestions I think my only way forward is as follows:

1. to prove the integrity apply a horizontal force to prove shear and flexural strength. To do this I need a value for this force. Can anyone give me the name of a publication which proposes such a force?

2. Instead of proving the resistance against driven rain I think I have to apply a coating. This coating may be a silane type. It should be clear and possible to apply on top of the existing exterior paint. Does anyone know of such a coating?

Chapter A, Section 1.2 of the UK Bldg regulations will provide you with loading references.

However, remember that you are dealing with Thailand, and the BS standard may not have wind loading criteria for that region...but I'm sure folks at BRE in the UK or AIT in Bangkok will be in the position to provide it. And if the structure is in a location where it could be subject to hazards of flooding, I imagine fload loading will have to be taken into account.

Unless very necessary, I'd try and steer clear of in-situ testing (airbag, IR etc) because it can become very expensive. This is why I asked if the building was inspected by an approved individual...and if that was the case, then it should just boil down to performing analysis and verification of design...in so far as the structural aspect is concerned.

Have you considered hiring a consultant who comprehends local regulations and practice? There must be numerous MIStructEs or C.Engs who fit the bill. I understand that in the aftermath of the Dec 2004 Tsunami, building control regulations have been tightened up in the Kingdom.

The relevant Austr. Code is 'AS3700-Masonry Structures' I've pasted the most relevant section for your dilemma below. As can be seen, this tests a localised part only and is destructive to that area. A number of tests would need to be done to obtain a representative strength. The critical lateral loading is either wind or earthquake for the location of the building.

I am a bit perplexed as to what the consultant expects, can't they be more specific, ie. what clause of the technical specification doesn't the masonry allegedly comply with?

I trust the normal rules apply; testing costs are borne by the client if the walls are shown to comply.

Appendices C and D could be emailed, except posting of email addresses on this forum is not allowed. If you know an alternative let me know.


APPENDIX I
TESTING OF IN SITU MASONRY
(Informative)
I1 GENERAL
Where it is required to test properties of in situ masonry, it may be tested for either
compressive or flexural strength.
I2 PREPARATION FOR TESTING
Part of a wall that is representative of the masonry under test shall be selected.
For compression strength testing, prisms containing at least three courses and having an
aspect ratio (height-to-width ratio) of between two and five shall be cut from the wall by
methods that ensure no damage to the samples.
For flexural strength testing, masonry above the test area shall be carefully removed as
necessary, to provide access for the bond wrench, and perpends shall be cut through, both
by methods that ensure no reduction in strength to the joints to be tested, so that the only
resistance to flexure is provided by the bed joint to be tested.
I3 TESTING
Compressive and flexural strength testing shall be in accordance with the relevant
paragraphs of Appendices C or D, as appropriate.

Great stuff apsix. You have provided some very useful information.

In the US, section 2105.3 of the IBC (model code) has criteria for testing prisms from constructed masonry..but approval from the building dept (building control agency) must be granted. The testing standard ASTM C 1314, permits aspect ratios of between 1.3 to 5, which is essentially the same as the requirement you cited above for prisms.

While these tests provide pertinent information, if there was no inspection/observation of the construction of walls, IMO, there will be no assurance that: the proper size and spacing of reinforcement was used, required cells were grouted...etc...unless supplemented by NDE techniques.

apsix... in Canada, costs for testing are generally borne by the client if tests are successful and by the contractor if unsuccessful and re-testing is generally borne by the contractor. Thanks for the info about down under.

Dik

thanks to all for the posts. I am now reviewing and discussing with a possible testing agency. More later....

Zambo -

I think it is a good move to look to an independent testing organization.

After looking at projects and dealing with contractors working in over 35 countries, I quickly learned that private projects in your region can have some unusual owner/builder/designer/contractor relationships that are quite different than the the conventional North American construction projects.

The concept of traditional detailed specifications and inspections may be varied, especially when a convoluted "in-house" concept is used, but the owner must be satified in the end.

I have seen some amazing projects completed flawlessly, but at first I was terrified by the controls and procedures when I looked at it from the outside. After understanding the process, I now have a different perspective regarding the system. Now many years later, the projects are still a credit.

Often, it takes an outside organization to satisfy the parties and get the project completed and signed off to everyone's satisfaction.

Dick

concretemasonary,

I think you can see the predicament. An engineer wants us to carry out a test, the test is not defined. We cannot prove that evrything is OK because if we have a design check carried out then we will be asked about the workmanship. If we open up the wall to show the quality is OK then we can be asked to prove that all panels are identical.

I have been advised that for wind loading I should allow 0.5KN/m2 x SF 1.5. Our panels are 12 x 6m which if we test the full panel gives a considerable load.

So the first step is a design check. Next I will investigate the practicality of a load test. The other option is an independant report.

So far no advise received on an external coating to protect against driven rain.

From what you're telling us the demands seem unreasonable; how can you ever know that construction quality is 100% consistent?

Re waterproofing; single leaf block housing is used in some regions in Australia. Section 10.4 of the linked document discusses surface finishes;