Rak-43.3312 Repair Methods of Structures IIPlanning of Condition Survey and Repair Measures

Group 19

Sanjay SreekalaBurak ErkanGhaffar Khan

12.02.2014Petri MutanenKari ParilaKim Warma

Group Members

Agenda

I. Introduction

II. Condition Survey Methods

III. Condition of the Case

IV. Further Research Needed

V. Proposed Principled Repair Methods and Estimated Remaining Service Life

VI. Discussion

VII. Conclusion

I. IntroductionGeneral

• Location: Töölö, Helsinki• Residential building

– 7 storeys– 52 rental apartments

• Sheltered location and light traffic

• Technical documents not available– No exact data of the condition– No previous condition surveys More theoretic point of view

• HUT research team visit in 2003-2004– list of anticipated deterioration mechanisms

I. IntroductionFaçade properties

• Rough cast made on brickwork• Light brown color• Two facades

– Main façade facing south-west– Courtyard façade facing north-east

• Balconies on six storeys– Concrete slab with precast concrete railings

• Major façade renovation made in 1997– External rendering with an insulation layer

II. Condition Survey Methods

• Visual evaluation and assessment

– Frost damage

– Brick spalling

– Peeling of external rendering

– Cracking of concrete

– Pipe corrosion

II. Condition Survey Methods

• Formation of organic moss

– Mechanical damage

• External wall insulation

rendering

• Visual assessment data

– Considerable moss growth on

façade

– Cracking and contamination in

balconies

II. Condition Survey Methods

• Frost deterioration of external rendering

• Joint degradation and pipe corrosion

• Evidence of carbonation and structural steel corrosion

in the past

• Crack development in footing

• broken tiles at the building entrance

II. Condition Survey Methods

• Overall performance of the building satisfactory

• Structural integrity not affected

• Minor repairs needed to ensure full efficiency

III. Condition of the Case

• More than 50 years old

• Condition is relatively good

• Better than in many younger buildings

• No special conservation status

• Major repairs possible

• The current condition can be easily maintained

• The condition can be improved by new repairs

III. Condition of the Case

• Small signs of deterioration visible in several parts of the facade

• None of them is overwhelmingly severe• But they will become worse is nothing is done• Before the last renovation new insulation was needed.• Also the rendering needed repair• Now the mortar is in satisfactory condition

III. Condition of the Case

• There are many minor and some major cracks• Evidence of moisture, especially near he windows• Mainly aesthetic problem, but in some spots more

severe, mold?• Contamination is generally light• Footing has some cracks, level is light• Mechanical damage

III. Condition of the Case

• Floor tiles cracked• Peeling off has started, average level• Degradation of joints, not always visible• Balconies are in worst condition, even after last

renovation• Moisture and joints are clearly deteriorated• Balcony slabs are the biggest concern• The Souts-West facade is more damaged

III. Condition of the Case

• Older data revealed structural deterioration:– Carbonation– Reinforcement steel corrosion– Frost damage– Some parts of the structure do not need attention, e.g. the

bricks

• More infromation should be gathered before the next repair

IV. Further Research Needed

• Investigating the previous condition surveys– Research done according to visual inspection, provided Excel

sheet and theorotical knowledge

• No visual dimensional defects– Possible bowing of rendering in higher elavations

• Terrestial laser scanning

• Existing defects observed during visual inspection– Frost Damage, Peeling of ext. Rendering, Cracking of Concrete

and Moist• Thin Section Analysis• Carbonation and Chloride levels

IV. Further Research Needed

• Tensile Strenght Testing• Bonding Condition of Facade

– Nothing seen durin the visual inspection• Hammering Technique

• Asbestos Analysis– Since no backgroung information available, it is still a question– Although last renovation done 17 years ago. It Shall be checked

in order to be on safe side

V. Proposed Principled Repair Methods and Estimated Remaining Service Life

Elastic expansion jointApplying new coating

V. Proposed Principled Repair Methods and Estimated Remaining Service Life

Base plate Down pipes and nearby structures

V. Proposed Principled Repair Methods and Estimated Remaining Service Life

Mortar patching for footing and applying new coating

Replacement or surface treatment of wooden material

V. Proposed Principled Repair Methods and Estimated Remaining Service Life• Option A

– Low-cost repair method

– Insecurity with the long-term efficiency

– Relatively cheap and quickly done

– Service life from 10 to 15 years.

V. Proposed Principled Repair Methods and Estimated Remaining Service Life1. Material tests

2. Removing deterioration factor

3. Removing deteriorated mortar parts and applying mortar patching

4. Refining old coating and appyling new coating.

V. Proposed Principled Repair Methods and Estimated Remaining Service Life• Option B

– High costs

– Long-term efficiency reliable.

– Working and environment safety plans are needed.

– Service life up to 30 years.

V. Proposed Principled Repair Methods and Estimated Remaining Service Life1. Removing deterioration factor

2. Demolition of old surface rendering

3. Cleaning of the visible surface

4. Strengthening of the under layer

5. New surface rendering

6. Coating of the rendering

VI. Discussion

• Overall building in Satisfactory Condition.– Aesthetic Damages (frost damage, brick spalling, peeling of

external rendering, cracking of concrete, pipe corrosion, mould, mechanical damages, discoloration etc)

– Footing has cracks– Degradation of joints (needs attention)– Possible Carbonation and Steel Corrosion (previous survey)

VI. Discussion

• No need for demolishing• Building can survive without repairs for the time being

(No desirable)• Further research / survey needs to be conducted

VII. Conclusions

• New Condition Survey should be conducted- This will determine future action

• Minor repairs needed• Repairs done in 1997 needs to be checked• Some critical areas needs detailed testing and possible

counter measures