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R. GOVIND - M.H. YILMAZ, 2017; ICBEST 2017
Facade Failures, Seminar Article

FAÇADE FAILURES DUE TO PROJECT DESIGN DEVELOPMENT AND WORKMANSHIP

Abstract

There has been and will always be failures in construction business, like any other business. Engineers and Consultants are paying serious attention to prevent and learn from them.

There is nothing stationery against the nature forces. It is quite often in the façade industry, either designers pay less or no attention to the building movements or underestimate its interactions. In the building envelope, the impact will be so severe with devastating damages to the building and its services; resulting expensive rectifications and disruptive occupancy of the building.

Mistakes are being made during the design, fabrication and installation stages. However most of them are still caused by, misinterpreting the basic physics rules and the main principles. Every failure tells us something, only if we listen to it correctly. We must not only criticize, punish or just fix it, but learn from them. We need to empathize to see which mistakes are repeated, which main principal is not understood by the designers and installers.

Basic design principles of joints and allowances for adequate movements start from these typical facade details. Simple verifications and design process may avoid disruptive impact on post completions.

Not only avoiding failures, but also using the information, researching and collecting data, will help us improve the Facade sector.

On this note two cooperating Facade Consultant Companies, each working in different regions and experienced in dealing with problematic issues, came together to share the experiences by presenting a detailed work, on reasons, facts, statistics, solutions, suggestions and future preventions on Facade Failures.

Keywords

Façade Failures, Curtain Wall damages, Cladding Failures, …

1. Introduction

Buildings as homes, offices, hotels or hospitals, are man-made structures intended for human use. These are shelters and physical divisions of the human habitat which supply comfort and safety.

Many of the definitions of Building say “a structure with a roof and wall for people use”. Wall is something mentioned primarily and we believe it refers to the outer walls.

Outer walls of the building, together with the windows, glazings and claddings, are either a border or a filter between the indoor and outdoor conditions. These are the elements that provide most of the comfort conditions we need.

The severity of the problem, with the building envelope, may vary from a minor performance loss to a devastating collapse, but in either case our comfort or more critically our safety will be under threat. Therefore this means, the purpose and functionality of this element of the building is not succeeded.

There are and have been many problems occurred with the windows, curtain walls and claddings (envelope) of the buildings. And mainly we have learned from them a lot. But the technology has developed very fast. The Investments are getting larger every decade, also the size of the buildings and complexity. Unfortunately the speed of learning from past mistakes is not enough to keep up following.

It is not possible to overview all mistakes and not necessary to examine the ones that are not repeating. In this study, we will consider some of these failures and mistakes through our 50 years old experience and daily facts from some cases.

Many of these failures due to miscalculations or poor engineering are studied before. Furthermore there are more complex problems such as ‘nickel-sulfide inclusion’, which causes serious concerns on glass applications. Here we will mainly focus on the mistakes or misses that were made during the designs, shop drawing preparation or design development and implementation stages including workmanship issues and construction failures. That we believe, these could have been easily prevented with right approach and checks in place. And we will try to find what reality lies behind these mistakes, we will try to go to the roots and find if there is a common solution.

2. Methodology

The authors of this paper are from Turkey and India, consultants of projects mainly in Turkey, Singapore, Malaysia, Russia, India, North Africa and middle east countries. There are of course some similarities and differences of the failures. We are going to show some case studies, and some other examples. These are some mistakes that we observed in different projects. We have used examples from different projects in each single case study. So we can tell that these are common mistakes or common problems.

Failures must be sorted in types. Miscalculation and poor engineering problems, materials and supply chain problems, design problems and workmanship problems are the most important ones. We will focus on the last two.

2.1 Case Study 1

In fact the first case study is not only one case, this is one common problem from three different actual projects of FMT Façade Consultants. The same mistake has been done by the designers during the shopdrawing phase and also by the technicians during the installation.

Let’s have a look at some design development stage problems;

The first project is in Istanbul, erected recently (year 2014). Below drawing was submitted by the façade contractor as the shopdrawing. The Façade of this part of this building has been designed as “window wall”, glazed facades are located between slabs and the slab edges are covered with metal sheet cladding. Therefore in each floor there is a bottom end of the glazed façade. Because of the heights of the floors and since in Turkey there is not any developed window wall systems such as in the U.S., usually the façade specialist are using Stick Curtain wall system elements.


Figure 1, submitted detail of Istanbul1 Project

This is a Stick Curtain wall system, used as window wall, and the façade contractor submitted this drawing for the bottom connections. Façade Consultant was involved in the project after installation started, to inspect the problems in this project.

As it can be seen, there is an insulation membrane shown with red. And the technicians in the jobsite applied the membranes exactly as they are in the drawings.

Figure 2, the work on the site

As shown in the above picture, technicians kept respecting the shopdrawings. And as it can be seen in the picture, the water insulation is in front of the system elements.

Below drawing was an explanatory warning to the Contractor.

Figure 3, graph shows misplacement of membrane

And also water drainage pipes were not used. The result is shown in the pictures below.

Figure 4, water leakage

These leakages were experienced after the main contractor was warned with the report including figure 3 above. Finally the façade specialist, used drainage fittings (pipes) and sealed the bottom line of the system in order to direct the water out.

Figure 5, water drainage fitting

This case shows us that neither the white collar people preparing these drawings nor the blue collars, have any idea about the façade system, how the water moves, how the pressure difference helps water infiltration and what condensation is.

These are all basic principles that can only be learned through the scientific approach. And must be taught to all façade teams including the installation technicians.

Another design mistake with the same problem;

Figure 6, Submitted Detail from Moscow Project

But this case is from another city, another Country and by another Façade specialist. The Russian contractors did the same mistake in their shopdrawings.

Fortunately, Façade consultant was involved during the design development stage so the contractor was warned and they corrected these details for allowing the water drains outside.

In these two examples the problem was caused by the shopdrawing designer, but below example shows us even though the drawing was correct, the installation crew made the same mistake;

Figure 7, Installation of Istanbul2 Project

2.2 Case study 2

Below example is from India.

As we have mentioned, there is nothing stationery against the nature forces. It is quite often in the facade designs industry, either designers pay no attention to the building movements or underestimate its interactions.

The impact will be so severe in the building envelope with devastating damages to the building and its services. There will be expensive rectifications and disruptive occupancy of the building as a consequence. Some facts of similar instances from a building investigation have been presented here.

Figure 8, Building (in Mumbai) with shattered glass units

Figure 9, Quick Facts; Key figures of glass breakages of the building

Following; showing pattern of failure modes of Unitized Curtain Wall systems and causes

Figure 10, Failure modes

Pictures illustrate the impact and post instance scenario of façade glazing panels behaviors. Excessive joints movements are evident in these pictures of external and internal façades

Figure 11, External view of joints failures

Building Facades – Movements and joint designs;

Basic design principles of joints and allowances for adequate movements start from these typical facade details.
Simple verifications and design process may avoid disruptive impact on post completions.

Figure 12, Joint design illustration

2.3 Case study 3

Below there are some pictures from a very common mistake about the thermal movement ignorance. Either the designers or the installation crew, underestimated the thermal expansions.

These examples are from Istanbul and Moscow.

Figure 13, Spacer Left in the expansion Joint

Figure 14, Temporary Adjustment Screw Left in the expansion Joint

            

Figures 15&16, Expansion not allowed with fixed bolts.

It is clearly seen that, in these four different jobsites, the façade specialist installation crew have no idea about the thermal expansions and thermal expansion joints.

Therefore these cases are showing us the importance of the scientific facts and how easily these facts are underestimated due to the lack of knowledge and education.

3. Results and Discussion

Failures are threats to human life and safety, moreover failures cause loss of time, money, prestige and most importantly precious human life.

What we have seen in these case studies could have been prevented easily if the designers or implementing team had specific skills and experiences. On the other hand it is very obvious that, overall skills and manpower of some building envelope industry and supply chain are trained and already upgrading their skills as well as the adequate checks and supervisions are completed.

For example, the system designs of well known system house companies are tested and verified or IGU’s that are obtained from producers are under well QAQC procedures. But when it comes to the construction phase and the time is one of the most important issues, then the controls and verifications are getting weaker.

System houses design the systems and their components very well and describe it in their manuals sufficiently, but when it comes to connect them with other structures, mount to the building structures, both the design developers of the construction, the crew preparing the shopdrawings, and the foremen plus workers skip some crucial basics of physics and general rules.

Pressure differences – pressure equalization, building movements, pressure gradients of the facades, thermal movements are the most important examples of these rules.

It seems that those technical teams do not have enough education about the basic physics rules. Of course we are speaking about our regions but let us not forget that these are the fastest growing regions and the demand of buildings is still increasing.

It is very clear that the project detail designers and the installation crews must be educated about the building physics, they need to know why there is a thermal expansion gap or what is water drainage.

The façade specialist companies must give importance to their inspections as well as their internal educations. I have seen some internal random inspections of façade specialist companies but only in few cases. Usually there is no double check with the stage of design development – shopdrawings and installation. On the contrary it is observed that the controls during the factory productions are sufficient enough. Therefore the façade specialist must give the same importance to the jobsites as well as their factories.

Another safe way of controlling the jobsite phase must be done by the developers or main contractor by using the façade consultants.

Designer’s Skills vs Practice

Matrix illustrates the relationship between the designer’s skills and possible outcome of the designs.

Figure 17, Skills

Figure 18, Rating Design

Either during the designing stage or the site works, the power of nature and materials must not be underestimated, on the contrary these must be calculated very carefully. Even though the correct application is shown in the drawings, the installer can underestimate and continue with his own way. This implicates that the education of both the designers and the installers, has a very high importance and necessity.

References

Yilmaz, H. (1999). Cephe Sistemleri ve Cephe Kaplamaları, YEM Yayınları.
TS EN ISO 13830: Curtain Wall Product Standard, 2016.

ICBEST Istanbul, 15-18 May 2017, Istanbul / Turkey

 

 

 

 

 

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