This shows you the differences between two versions of the page.

Link to this comparison view

Next revision
Previous revision
whe [2019/01/22 15:43]
Vitor Silva created
whe [2019/02/12 01:45] (current)
Vitor Silva
Line 1: Line 1:
-====== ​MEXICO ​======+====== ​Italy ======
-===== Reinforced concrete multistory buildings ​=====+===== Historic masonry block of flats =====
 ==== 1. General Information ==== ==== 1. General Information ====
-**Report #:** 115+**Report #:** 206
-**Report Date:**+**Report Date:​** ​2010
-**Country:​** ​Mexico+**Country:​** ​Italy
-**Housing Type:**+**Housing Type:​** ​masonry
-**Housing Sub-Type:**+**Housing Sub-Type:​** ​unreinforced
 **Author(s):​** Mario Rodriguez, Francisco G. Jarque **Author(s):​** Mario Rodriguez, Francisco G. Jarque
-**Last Updated:**+**Last Updated:​** ​2012
-**Regions Where Found:​** ​Buildings of this construction ​type can be found in four important regions in Mexico: 1.- Mexico City and metropolitan areacapital city of Mexicowith 30% of the total housing stock in the country2.- Guadalajara,​ Capital City of the State of Jalisco, high seismicity 3.- Monterrey, Capital City of the State of Nuevo Leon, low seismicity4.- Cities at resort areas of the Pacific coast, such as Acapulco, Ixtapa, Huatulco. This type of housing construction is commonly found in urban areas.+**Regions Where Found:​** ​This housing ​type is in Abruzzo RegionProvince ​of L Aquilaand is very frequent ​in small medieval villages built in mountainous areas 
 +90% of the Province ​of L Aquila is mountainous and about 50% of its municipalities have less than 1.000 inhabitantsUrban structures and buildings built since the Middle Age are very common
-{{  :​101200_115_02.jpg?​300|Reinforced concrete multistory buildings}} 
-**Summary:​** This report describes Reinforced Concrete ​(RCmultistory residential buildings in MexicoThis type of construction is found mostly in large cities where space limitations lead to this type of solutionTypically buildings of this type have eight or more stories. Members of the middle and upper classes ​are the target market ​for this type of constructionIn areas of low seismic risk, waffle slab floor systems without structural RC walls are preferred by developers primarily due to their speed of constructionIn areas of medium to high seismic riskit is typical for this type of building to have dual systemwhich combines RC moment frames and RC structural walls as the main lateral load resisting elements. The RC floor systems ​are constructed ​of waffle slabs or solid slabsRC buildings account for about 80% of the entire housing stock in MexicoBuildings constructed after 1985 are expected to perform well under seismic forcesespecially in Mexico City, where the building ​construction code has been substantially updated ​to incorporate lessons learned during ​the 1985 earthquake.+**Summary:​** This housing type is typically built on sloped terrain ​(pic.1). Buildings share common walls with adiacent buildings and the average number ​of floors ranges from 3 to 5 (pic2). The ground floor is sometimes used as cellar ​or warehouse, whereas ​the upper floors ​are used for residential purposesThe walls are built using lime mortar ​to connect elements that are either bricks or rubble stones or a mix of both in which the bricks are positioned in thin layers every 1.5 - 2 min order to align and stabilize the stones. The last floor (attic) ​is sometimes more recent (probably from the beginning ​of the XX cent.) and built with different materials (i.e. tuff) or specific construction techniques (i.e. "​muro ​cassetta"​whose bricks are positioned in order to made a very light structure). 
 +The floor structures ​are vaults ​of different shapes, materials and resistance depending on the functionAt the lower levels they are usually thick and made of stones connected by lime mortar, whereas at the upper floors they are made by bricksAt the last level the vaults ​are usually made by one single brick layer and their sides are usually kept half empty with no walkable floor. 
 +The roof is made of timber and it is double pitchedsloping down towards ​the front and rear walls. This building ​type has shown a good seismic performance,​ because the adiacent blocks work all together ​to stand the earthquake
 +Strenghtening interventions have been carried out after the main earthquakes.
-**Length of time practiced:​** ​51-75 years+**Length of time practiced:​** ​More than 200 years
-**Still Practiced:​** ​Yes+**Still Practiced:​** ​No
-**In practice as of:**+**In practice as of:** nan
-**Building Occupancy:​** Residential, ​20-49 units+**Building Occupancy:​** Residential, ​5-units
-**Typical number of stories:​** ​10-25+**Typical number of stories:​** ​3-4
-**Terrain-Flat:​** ​Typically+**Terrain-Flat:​** ​Never
 **Terrain-Sloped:​** Typically **Terrain-Sloped:​** Typically
-**Comments:​**+**Comments:​** ​The building type dates back to the middle ages with a complex later evolution over time expecially since the 18th century.
- ---- photogallery show ---- namespace : .:report115 title : Reinforced concrete multistory buildings photo gallery description:​ General Information photos copyright : Photos by Mario Rodriguez and Francisco G. Jarque posterimg : img_1196.jpg autoplay ---- 
-----+==== 2. Features ==== 
 +**Plan Shape:** Rectangular,​ with an opening in plan
-<​code>​ +**Additional comments on plan shape:** The plan and the overall shape of the buildings are influenced by the orography. People tried to build as much regurarly as possible, but the result were rectangules with not right angles and sides with very different measures. Sometimes walls are curved.
-\\  ==== 2Features ==== +
-**Plan Shape:** Rectangular,​ solid+**Typical plan length(meters):** 3 - 4 
-**Additional comments on plan shape:**+**Typical ​plan width (meters):** 3 - 4
-**Typical ​plan length ​(meters):​** ​40+**Typical ​story height ​(meters):​** ​2.5 - 3.5
-**Typical plan width (meters):** 25+**Type of Structural System:** Masonry: Stone Masonry Walls: Rubble stone (field stone) in mud/lime mortar or without mortar (usually with timber roof)Masonry:​ Unreinforced Masonry Walls: Brick masonry in mud/lime mortarMasonry:​ Unreinforced Masonry Walls: Brick masonry in mud mortar with vertical postsMasonry:​ Confined Masonry: Clay brick/tile masonry with wooden posts and beamsWooden Structure: Load-bearing timber frame: Masonry with horizontal beams/​planks at intermediate levels
-**Typical story height (meters):** 3.2+**Additional comments on structural system:** In the same structure there are usually different construction systems. 
 +It depended mainly on the availability of building materials, on the position of the single construction system as part of the overall structure and on the history of the buildings, to whom new rooms were added as families grew.
-**Type of Structural System Masonry:** Structural Concrete: Moment Resisting Frame: Dual system ​Frame with shear wall+**Gravity load-bearing & lateral load-resisting systems:** Gravity load-bearing ​system: thickness and materials depend on the floor level.  
 +Walls are thicker at the ground floor and thinner at the upper levels. They are usually made by a mix of bricks and rubble stones in which the bricks are positioned in thin layers every 1.5 - 2 m, in order to align and stabilize the stones.  
 +People used to reinforce perimetral corners placing shaped stones usually up to the 2nd floor. 
 +At the upper level there are often tuff walls or characteristic structures such as those called "muri a cassetta"​. They are made by two-wythe walls, in which every two courses of bricks laid edge on there is one course laid face-up, to connect the vertical bricks. The space between the vertical layers is empty, so that the thermal performance of the structure benefits from it and the wall is light. 
 +Vaults at the upper floors are often supported by timber frames filled by a partition made by a one-wythe wall, whose bricks are laid edge on. The load bearing structure and the partition are covered by plaster and the wall thickness is about 10 cm. 
 +The lime mortar joints are 3-5 mm thick.
-**Additional comments on structural system:** The vertical load-resisting system is reinforced concrete moment resisting frame. Columns, beams and solid or waffle slabs. The lateral load-resisting system is reinforced concrete structural walls (with frame). Moment resisting frames are used in low seismic areas and dual systems (combination of frames and RC walls) are used in medium and high seismic areas. In dual systems, shear walls are usually located at the building core and moment frames are located at the building perimeter.+**Typical wall densities in direction 1:** 10-15%
-**Gravity load-bearing & lateral load-resisting systems:**+**Typical wall densities in direction 2:** 10-15%
-**Typical ​wall densities ​in direction 1:** 1-2%+**Additional comments on typical ​wall densities:​** ​nan
-**Typical wall densities in direction 2:** 1-2%+**Wall Openings:** Every room has usually one window on the external walls. 
 +They aligned the windows upright on the facades, but the needs of residents and owners changed over time so that the existing opening layout have been often modified. Misalignments are very common. 
 +The openings account for approximately 10% -15of the wall surface area.
-**Additional comments on typical ​wall densities:**+**Is it typical ​for buildings of this type to have common walls with adjacent buildings?:** Yes
-**Wall Openings:** Mostly 2 openings are constructed at floor levelsleaving space for elevators ​and stairsThese openings are commonly located at the center ​of floor systems and are surrounded by concrete wallswhich are part of the lateral load resisting systemTheir sizes vary but typical dimensions ​are 2 x 5 m for stair ways and 2.5 x 2.5 m for elevators. Openings for doors are also located in RC walls. These walls are usually located at the building core and is unusual to locate RC walls at the building perimeter. Partitions in RC buildings for residential construction ​are usually ​constructed with clay/​concrete blocks.+**Modifications of buildings:** Door and window ​openings ​have often been modified. Very frequent modifications ​are misalignmentsenlargements,​ windows changed in balcony doors and windows bricked up and opened in different positions. 
 +The layout ​of apartments is quite irregular due to changes occurred over time.  
 +As families expandedthey built new storeys or just part of them or they bought rooms from the neighboursThis is the reason why inside the single flats there are often short flights of stairs ​and the plans are usually ​irregular, sometimes almost "​labyrinthine"​.
-**Is it typical for buildings of this type to have common walls with adjacent buildings? ** 
-**Modifications ​of buildings** A typical pattern for the modification of RC buildings is the demolition of partitionswhich are not part of the lateral load system for the building.+**Type of Foundation:** Shallow Foundation: Rubble stonefieldstone strip footing
-**Type of Foundation:** Shallow Foundation: Reinforced concrete isolated footingShallow Foundation: Reinforced concrete strip footingShallow Foundation: Mat foundationDeep Foundation: Reinforced concrete bearing pilesDeep Foundation: Reinforced concrete skin friction pilesDeep Foundation: Cast-in-place concrete piersDeep Foundation: Caissons+**Additional comments on foundation:** nan
-**Additional comments on foundation:**+**Type of Floor System:** Vaulted masonry floor
-**Type of Floor System:** Other floor system+**Additional comments on floor system:** The traditional ​floor system ​is the vaulted masonry floor. 
 +We currently also find the shallow-arched masonry floor and the metal beams light flooring. The first one was introduced at the beginning of the XX cent and in particular after the earthquake occurred in 1915. The second one was introduced after the earthquake occurred in 1984.
-**Additional comments on floor system:** Structural concrete: Solid slabs (cast-in-place);​ Waffle slabs (cast-in-place);​ Flat slabs (cast-in-place);​ Solid slabs (precast) In most design of RC buildings for residential construction,​ all diaphragms are considered rigid. 
-**Type of Roof System:**+**Type of Roof System:​** ​Wooden structure with light roof covering
-**Additional comments on roof system:​** ​In most design of RC buildings for residential construction,​ all diaphragms are considered rigid.+**Additional comments on roof system:​** ​The traditional roof system is the wooden structure with light covering. 
 +We currently also find the cast-in-place metal beam-supported hollow flat tiles and concrete roof, which was introduced after the 1984 earthquake
-**Additional comments section 2:** When separated from adjacent buildings, the typical distance from a neighboring building is 0.20 meters. +**Additional comments section 2:** nan
- +
 ==== 3. Buildings Process ==== ==== 3. Buildings Process ====
-=== Description of Building Materials === 
 ^Structural Element ​ ^Building Material (s)  ^Comment (s)  | ^Structural Element ​ ^Building Material (s)  ^Comment (s)  |
-|Wall/​Frame ​ |Concrete  ​|f'c= 30 MPa  ​+|Wall/​Frame ​ |Mix of bricks and rubble stones|average compressive strength: 256-413 N/cmq 
-|Foundations ​ |Concrete  ​|f'c= 25 MPa  ​+average shear strength: 6.2 - 9.0 N/cmq 
-|Floors ​ |Concrete  ​|f'c= 25 MPa  ​+(Baila, A., Binda, L., Borri, A. et al. (2011) - Manuale delle murature storiche, Analisi e valutazione del comportamento strutturale Vol.1, p. 292)
-|Roof  |Concrete  ​|f'c= 25 MPa  ​+|Foundations ​ |Mix of bricks and rubble stones or rock|nan
-|Other ​ |   ​  ​|+|Floors ​ |Brick vaults|nan
 +|Roof  |Wooden beams|nan
 +|Other ​ |nan|nan| 
 +=== Design Process ===
-----+**Who is involved with the design process?:** None of the above
-=== Design Process ===+**Roles of those involved in the design process::** The construction process was carried out by masons, so engineers and architect were usually not involved. ​
-**Who is involved with the design process?** Engineer or Architect 
-**Roles of those involved in the design process:** Local building codes require that a project be designed by a registered engineer. Architects are in charge of the building space distribution and of fulfilling the owner'​s requirements. Usually architects hire structural engineers for the design and construction of buildings. 
-**Expertise of those involved in the design:** 
-----+**Expertise of those involved in the design::** nan
 === Construction Process === === Construction Process ===
-**Who typically builds this construction type?:** Other+**Who typically builds this construction type?​** ​Mason
-**Roles of those involved in the building process** ​Typically this construction ​type is built by developers.+**Roles of those involved in the building process:** The construction ​was based on the mason'​s experience.  
 +Tricky works such as the construction of vaults were committed to specialized teams of masons
-**Expertise of those involved in building process** 
-**Construction ​process ​and phasing** RC buildings for residential ​construction in Mexico is mostly constructed by developersDepending ​on the type of soilexcavations for foundations is carried out with several types of excavator machineries. Ready-mix concrete is usually supplied for construction of these buildings. The construction of this type of housing takes place incrementally over time. Typically, the building ​is originally designed for its final constructed size.+**Expertise of those involved in building ​process:** Masons were supposed to meet the owner'​s needs, working on a budget and using the construction ​materials available ​in the areaTheir main ability consisted in finding the right balance among forces acting in different directions ​on light and thin structures. They basically had to make sure that the stiffness ​of all the structural elements was coherent as a whole so thatin the event of an earthquake, the building ​would perform a box-behaviour.
-**Construction issues** 
 +**Construction process and phasing:** The construction process was influenced by the owner'​s budget, the availability of materials, the characteristics of the area (orography) and of the surrounding buildings. 
 +The works usually took place in one phase. Sometimes at a later time, storeys or just single rooms were added in order to meet the owner'​s needs. 
 +The construction tools were simple. 
 +**Construction issues:** nan
 === Building Codes and Standards === === Building Codes and Standards ===
Line 134: Line 145:
 **Is this construction type address by codes/​standards?​** Yes **Is this construction type address by codes/​standards?​** Yes
-**Applicable codes or standards** ​There is not a national building code and only few local codes are available; thereforea number of regions in Mexico do not have building codes. In those cases some adaptations of the Mexico City building code are used. This code covers RC design and in most parts is based on the ACI 318 code. In some regions of the country where there is no local building code, the ACI 318 code is mostly followedIn Mexico Citythe title of the current building code is "​Reglamento de Construcciones del Distrito Federal"​ (Federal District Building Code). The year the first code/​standard addressing this type of construction issued was In Mexico City the first code provisions were issued in 1920 and the 1942 building code for Mexico City was the first that had seismic provisions. The most recent building code for Mexico City was released in 2004.+**Applicable codes or standards:** With Royal Decree-Law n.573, on 29 April 1915 the area was included among the seismic onesdue to the earthquake occurred on 13 January ​ 2015This Royal Decree-Law ruled both new construction and reparation works on damaged buildings (Title II ReconstructionsTitle III Reparations)
-**Process for building code enforcement** Building has to be designed by code requirements and plans need to be approved by a registered engineerPlans are submitted to a code enforcement agencyHoweverusually the structural design is not reviewed by these agencies. It is assumed that the structural design is a responsibility only of the registered engineer. Building permits ​in Mexico City are granted by the local agencyIn other parts of the country where there are local building codes these permits are granted by the corresponding local code enforcement agencyAfter the permit is grantedthe code enforcement agency usually does not send inspectors ​to the construction site.+Relevant following regulations:​ 
 +- Royal Decree-Law n.2089, 23 October 1924 
 +Law n642 February 1974, Provvedimenti per le costruzioni con particolari prescrizioni per le zone sismiche (Measure for constructions with specific rules for seismic areas) 
 +- Ministerial Decree 16 January 1996, Norme tecniche per le costruzioni ​in zone sismiche (Technical standards for constructions in seismic areas) 
 +- Ministerial Decree 14 January 2008, D.M2008 Norme Tecniche per le Costruzioni (Technical standards for constructions)which includes how to repair existing buildings made by bricks and stones.
-----+The standard currently in force is: Decree 17 January 2018, Aggiornamento delle "Norme tecniche per le costruzioni"​ (Update of the Technical standards for constructions). 
 +Technical suggestions and best practices are included in "Linee guida per riparazione e rafforzamento di elementi strutturali,​ tamponature e partizioni"​ written by ReLUIS consortium 
 +**Process for building code enforcement:​** nan
 === Building Permits and Development Control Rules === === Building Permits and Development Control Rules ===
Line 144: Line 163:
 **Are building permits required?** Yes **Are building permits required?** Yes
-**Is this typically informal construction?​** ​No+**Is this typically informal construction?​** ​Yes
-**Is this construction typically authorized as per development control rules?​** ​Yes+**Is this construction typically authorized as per development control rules?​** ​No
-**Additional comments on building permits and development control rules ** +**Additional comments on building permits and development control rules** ​All these buildings are currently subjected to national and local codes that are much more recent than the constructions themselves
- +
 === Building Maintenance and Condition === === Building Maintenance and Condition ===
-**Typical problems associated with this type of construction** +**Typical problems associated with this type of construction:** These buildings ​need structural strengthening due to their age, their structural fragility, the poverty ​of their materials and even because throughout the centuries they have been subjected to several hearthquake tremors, which made them every time weaker ​(incremental damage
- +
-**Who typically maintains ​buildings of this type?** Owner(s) or Renter(s)+
-**Additional comments on maintenance and building condition** Typically, the building ​of this housing ​type is maintained by Owner(s) ​and Tenant(s).+**Who typically maintains buildings ​of this type?** Owner(s)
-----+**Additional comments on maintenance and building condition** nan
 === Construction Economics === === Construction Economics ===
-**Unit construction cost** ​The construction cost for RC buildings ​ranges from 1,300 $US/​m2 ​to 2,200 $US/m2 depending on the type of apartments and location of the building.+**Unit construction cost:** This construction ​typology is no longer built and is usually replaced by other typologies made of reinforced concrete frames, whose cost ranges from 1.500 to 2.500 euros/sq m
-**Labor requirements** Usually 3 weeks are required for the construction of each floor level in a building. However, this construction time could increase due to rain or shortage of developer'​s money during construction. 
-**Additional comments section 3** 
-----+**Labor requirements:​** nan
-==== 4. Socio-Economic Issues ====+**Additional comments section 3:** nan
-**Patterns of occupancy:​** Typically in RC buildings, each apartment is occupied by a single familyThe number of apartments in a building varies from building to building. Each building typically has 30 housing unit(s). Minimum 10 Maximum 48+=== 4Socio-Economic Issues ===
-**Number ​of inhabitants in a typical building of this construction type during the day:** >20+**Patterns ​of occupancy:** One family per house
-**Number of inhabitants in a typical building of this construction type during the evening/​night:** >20+**Number of inhabitants in a typical building of this construction type during the day:** <5
-**Additional comments on number ​of inhabitants:** In the evening/​night ​the inhabitants number greater than 50.+**Number ​of inhabitants ​in a typical building of this construction type during ​the evening/​night:** <5
-**Economic level of inhabitants:​** ​Middle-income class / High-income class (rich)+**Additional comments on number ​of inhabitants:​** ​Family units are usually small (<=4 people).  
 +They are often retired people
-**Additional comments on economic ​level of inhabitants:​** ​Economic Level: The ratio of price of each housing unit to the annual ​income ​can be 6:1 for middle ​class family and 5:1 for rich class family.+**Economic ​level of inhabitants:​** ​Low-income class (poor)Middle-income ​class
-**Typical Source ​of Financing:** Personal savings, Commercial banks/​mortgages,​ Government-owned housing+**Additional comments on economic level of inhabitants:** Retired people who live in these houses have often a low income. 
 +Families usually belong to the low or middle income class. 
 +Lots of houses are used as holiday homes by people from the area who live and work in other parts of the country. 
 +In villages with beautiful views sometimes apartments are bought by foreigners from high-income class, who spend there their holidays or few months out of the year
-**Additional comments on financing:​** 
-**Type of Ownership:** Rent, Units owned individually (condominium),​ Long-term lease+**Typical Source ​of Financing:** Owner financedPersonal savingsInformal network: friends or relativesSmall lending institutions/​microfinance institutionsOther
-**Additional comments on ownership:**+**Additional comments on financing:** State aid for the reparation and strengthening of the buildings after earthquakes
-**Is earthquake insurance for this construction type typically available?:** No+**Type of Ownership:** RentOwn outright
-**What does earthquake insurance typically cover/cost:** Building insurance for residential construction is not a common practice in Mexico. One reason for this practice appears to be the high premium costs for covering seismic damage of buildings. Premium discounts are not available in Mexico for seismically strengthened buildings or new buildings built to incorporate seismically resistant features.+**Additional comments on ownership:** nan
-**Are premium discounts or higher coverages available ​for seismically strengthened buildings or new buildings built to incorporate seismically resistant features?:** No+**Is earthquake insurance ​for this construction type typically available?** No
-**Additional comments on premium discounts:**+**What does earthquake insurance typically cover/cost:** nan
-**Additional comments section 4:** Earthquake insurance for this construction type is typically unavailable. For seismically strengthened existing buildings or new buildings incorporating seismically resilient features, an insurance ​premium ​discount ​or more complete coverage is unavailable. Building insurance for residential construction is not a common practice in Mexico. One reason for this practice appears to be the high premium costs for covering seismic damage of buildings. Premium discounts are not available ​in Mexico ​for seismically strengthened buildings or new buildings built to incorporate seismically resistant features+**Are premium ​discounts ​or higher coverages ​available for seismically strengthened buildings or new buildings built to incorporate seismically resistant features?** No
-----+**Additional comments on premium discounts:​** nan 
 +**Additional comments section 4:** nan
 ==== 5. Earthquakes ==== ==== 5. Earthquakes ====
-=== Past Earthquakes in the country which affected buildings of this type === 
 ^Year  ^Earthquake Epicenter ​ ^Richter Magnitude ​ ^Maximum Intensity ​ | ^Year  ^Earthquake Epicenter ​ ^Richter Magnitude ​ ^Maximum Intensity ​ |
-|1985  ​|Michoacan Coast  ​|8.1  |   | +|1703|L'​Aquila|6.6|MI
-|1995  |Colima ​ |8  |   | +|1706|Campo di Giove (L'​Aquila)|6.6|MI
-|2003  |Colima ​ |7.6    ​+|1762|Poggio Picenze ​(L'​Aquila)|5.9|MI
- +|1904|Rosciolo ​(Marsica)|5.6|MI
----- +|1915|Paterno ​(Marsica)|7|MI|
- +
-=== Past Earthquakes === +
- +
-**Damage patterns observed in past earthquakes for this construction type:** The 1985 Michoacan earthquake has been the strongest earthquake in the Richter magnitude scale since a period starting in the 1940'​s. This earthquake had its epicenter in the Pacific coast, not really near urban areas. This feature has been typical in most earthquakes affecting Mexico since the 1940'​s. It follows that in the last few decades the RC system evaluated in this report has only been subjected to strong ground shaking in Mexico City. +
- +
-**Additional comments on earthquake damage patterns:** Collapse or severe damage in waffle-slab frame buildings was evident in the 1985 earthquake in Mexico City. +
- +
----- +
- +
-=== Structural and Architectural Features for Seismic Resistance === +
- +
-The main reference publication used in developing the statements used in this table is FEMA 310 “Handbook for the Seismic Evaluation of Buildings-A Pre-standard”,​ Federal Emergency Management Agency, Washington, D.C., 1998. +
- +
-The total width of door and window openings in a wall is: For brick masonry construction in cement mortar : less than ½ of the distance between the adjacent cross walls; For adobe masonry, stone masonry and brick masonry in mud mortar: less than 1/3 of the distance between the adjacent cross walls; For precast concrete wall structures: less than 3/4 of the length of a perimeter wall. +
- +
-^Structural/​Architectural Feature ​ ^Statement ​ ^Seismic Resistance  ​| +
-|Lateral load path  |The structure contains a complete load path for seismic force effects from any horizontal direction that serves to transfer inertial forces from the building to the foundation. ​ |TRUE  | +
-|Building Configuration-Vertical ​ |The building is regular with regards to the elevation. ​(Specify in 5.4.1 |TRUE  | +
-|Building Configuration-Horizontal ​ |The building is regular with regards to the plan(Specify in 5.4.2)  ​|TRUE  ​+
-|Roof Construction  ​|The roof diaphragm is considered to be rigid and it is expected that the roof structure will maintain its integrity, i.e. shape and form, during an earthquake of intensity expected in this area.  |TRUE  | +
-|Floor Construction ​ |The floor diaphragm(sare considered to be rigid and it is expected that the floor structure(s) will maintain its integrity during an earthquake of intensity expected in this area.  ​|TRUE  | +
-|Foundation Performance ​ |There is no evidence of excessive foundation movement (e.g. settlement) that would affect the integrity or performance of the structure in an earthquake |TRUE  ​+
-|Wall and Frame Structures-Redundancy  ​|The number of lines of walls or frames in each principal direction is greater than or equal to 2.  |TRUE  | +
-|Wall Proportions ​ |Height-to-thickness ratio of the shear walls at each floor level is: Less than 25 (concrete walls); Less than 30 (reinforced masonry walls); Less than 13 (unreinforced masonry walls);  ​|TRUE  | +
-|Foundation-Wall Connection ​ |Vertical load-bearing elements (columns, walls) are attached to the foundations;​ concrete columns and walls are doweled into the foundation |TRUE  ​+
-|Wall-Roof Connections  ​|Exterior walls are anchored for out-of-plane seismic effects at each diaphragm level with metal anchors or straps. ​ |TRUE  | +
-|Wall Openings ​ |   ​|N/​A ​ | +
-|Quality of Building Materials ​ |Quality of building materials is considered to be adequate per the requirements of national codes and standards ​(an estimate).  ​|TRUE  | +
-|Quality of Workmanship ​ |Quality of workmanship (based on visual inspection of a few typical buildings) is considered to be good (per local construction standards). ​ |FALSE ​ | +
-|Maintenance ​ |Buildings of this type are generally well maintained and there are no visible signs of deterioration of building elements (concrete, steel, timber). ​ |FALSE ​ | +
- +
----- +
- +
-**Additional comments on structural and architectural features for seismic resistance:​** +
- +
-**Horizontal irregularities typically found in this construction type:** Other +
- +
-**Vertical irregularities typically found in this construction type:** Other +
- +
-**Seismic deficiency in walls:** +
- +
-**Earthquake-resilient features in walls:** The use of walls provides a reduction in the expected seismic damage. +
- +
-**Seismic deficiency in frames:** In general, frames are very sensitive to reinforcement detailing. +
- +
-**Earthquake-resilient features in frame:** +
- +
-**Seismic deficiency in roof and floors:** They are not designed for specific seismic load paths, that is they are designed only for gravity loading. The current Mexico City building code is not clear in this aspect of floor system design. New detailing provisions enacted since the 1985 earthquake mostly addresses beam, columns and w alls, and not much on floor systems. +
- +
-**Earthquake resilient features in roof and floors:** +
- +
-**Seismic deficiency in foundation:​** +
- +
-**Earthquake-resilient features in foundation:​** +
- +
----- +
- +
-=== Seismic Vulnerability Rating === +
- +
-For information about how seismic vulnerability ratings were selected see the [[:​wiki:​seismic_vulnerability_rating.docx?​media=wiki:​seismic_vulnerability_rating.docx|Seismic Vulnerability Guidelines]] +
- +
-|   ​^ ​ High vulnerabilty ​ ^^  Medium vulnerability ​ ^^  Low vulnerability ​ ^| +
-|   ​|A ​ |B  |C  |D  |E  |F  | +
-|Seismic vulnerability class  |   ​| ​  ​| ​  |/ -  |o  |- /  | +
- +
-**Additional comments section 5 ** The overall rating of the seismic vulnerability of the housing type is E: LOW VULNERABILITY (i.e., very good seismic performance),​ the lower bound (i.e., the worst possible) is D: MEDIUM-LOW VULNERABILITY (i.e., good seismic performance),​ and the upper bound (i.e., the best possible) is F: VERY LOW VULNERABILITY (i.e., excellent seismic performance). +
- +
----- +
- +
-==== 6. Retrofit Information ==== +
- +
-=== Description of Seismic Strengthening Provisions === +
- +
-^Structural Deficiency ​ ^Seismic Strengthening ​ | +
-|Low lateral stiffness especially in waffle-slab buildings ​ |Several techniques for seismic rehabilitation have been used in Mexico. Among them the following can be mentioned: Column retrofit with RC or steel jackets, steel bracing of frames, use of new structural RC walls and even demolition of upper floors. However, current building code for Mexico City has no specific provisions for seismic strengthening of buildings. ​ | +
- +
-—- **Additional comments on seismic strengthening provisions:​** +
- +
-**Has seismic strengthening described in the above table been performed?:​** After the 1985 Mexico City earthquake several hundreds of RC buildings in Mexico City went through several of the seismic strengthening techniques here mentioned. +
- +
-**Was the work done as a mitigation effort on an undamaged building or as a repair following earthquake damages?:** Retrofit work is done in both cases but it is most common after earthquake damage. +
- +
-**Was the construction inspected in the same manner as new construction?:​** Yes +
- +
-**Who performed the construction:​ a contractor or owner/user? Was an architect or engineer involved?:​** Typically a contractor constructs a building under the instruction of an engineer. +
- +
-**What has been the performance of retrofitted buildings of this type in subsequent earthquakes?:​** Since the 1985 Mexico City earthquake a large number of residential RC buildings have been retrofitted;​ however, the effectiveness of these retrofits has not been tested by another strong earthquake yet. An evaluation of building damage during the earthquake in Mexico City showed that previous repair and/or strengthening interventions in RC buildings were not sufficient and in general showed a poor seismic performance. +
- +
-**Additional comments section 6:** +
-==== 7. References ==== +
- +
- +
----- +
- +
- +
----- +
- +
- +
----- +
- +
-=== Authors === +
- +
-^Name  ^Title ​ ^Affiliation ​ ^Location ​ ^Email  ​| +
-|Mario Rodriguez ​ |Professor ​ |Institute de Ingenieria Research & Education, Universidad Nacional Autonoma de Mexico ​ |Mexico City CP 4510, MEXICO ​ |mrod@servidor.unam.mx ​ | +
-|Francisco G. Jarque ​ |Engineer ​ |Garc  |Av. R, Col. Gral. Anaya DF 03340, MEXICO ​ |garciajarque@garciajarque.com ​ | +
- +
-=== Reviewers === +
- +
-^Name  ^Title ​ ^Affiliation ​ ^Location ​ ^Email ​ | +
-|Svetlana N. Brzev  |Instructor ​ |Civil and Structural Engineering Technology, British Columbia Institute of Technology ​ |Burnaby BC V5G 3H2, CANADA ​ |sbrzev@bcit.ca ​ | +
-|Walterio Lopez  |Oakland CA 94612, USA  |wlopez@ruthchek.com ​ |Walterio Lopez  |Oakland CA 94612, USA  | +
- +
-\\ +
  • whe.1548168191.txt.gz
  • Last modified: 2019/01/22 15:43
  • by Vitor Silva