Curso de Excavaciones

PROYECTO 320KEXCAVACIONES

Proyecto 320K - EXCAVACIONES

DefinicionesExcavacin Cualquier corte cavidad, depresin, en la superficie de la tierra hecha por el hombre, la cual puede producir falta de soporte del suelo en las operaciones del trabajo.Zanja Una excavacin angosta hecha bajo la superficie del suelo. En general la profundidad es mayor que el ancho, pero el ancho no supera los 15 pies (4.5m).Cajn de Zanjas es una estructura capaz de sostener la fuerza que impone un derrumbe, por lo tanto, protege a los trabajadores dentro de una estructura.Apuntalamiento Una estructura como un sistema metal hidrulico, mecnico o de vigas de madera que soporta los lados de la excavacin y est diseada para prevenir derrumbes.Pendiente una tcnica que emplea un ngulo especfico en los lados de la excavacin. El ngulo vara en base a los factores que afectan el sitio de la excavacin.


Enfoque del EntrenamientoLos mayores riesgos en una excavacin.Como protegernos de los derrumbes.Factores que poseen peligros para los trabajadores en excavaciones.El rol de la Persona Competente en el sitio de la Excavacin.


Peligros de una Excavacin Los derrumbes son los mayores riesgos. Otros Peligros Incluidos:Corte accidental de lneas subterrneas de servicio.Movimiento de maquinaria cerca del borde de la excavacin puede, causar un colapso.Acopio de material cerca de la excavacin.Asfixia debido a carencia de Oxgeno.Inhalacin de Materiales Txicos.Fuego. Excavaciones cerca de construcciones existentes.


Daos y MuerteLas Excavaciones es una de las operaciones mas peligrosas en la construccin.La mayora de los accidentes ocurren entre los 1.5 m. y 4.5 m. de profundidad.Usualmente no hay peligro antes de realizar una excavacin.


Peligros de DerrumbeThis excavation has inadequate support posts and egress accessEsta excavacin tiene postes de soportes inadecuados as como un inadecuado sistema de salida.


Condiciones PeligrosasEl peso y vibraciones de una Gra es una condicin peligrosa en una excavacin. Prohibido trabajar en estas condiciones.


Otros Peligros enlas ExcavacionesAcumulacin de agua

Deficiencia de Oxigeno

Humos txicos

Accesos y salidas inadecuadas

Cadas

Equipo Mvil


El agua es PeligrosaCuando el agua est presente en una excavacin es extremadamente peligroso entrarEstos trabajadores no estn utilizando cascos para protegerse de los materiales que caen


Agua = Peligro de DerrumbeEstos trabajadores deben de estar protegidos contra derrumbes. Observe el agua en la parte inferior de la zanja o excavacin esto es una condicin muy peligrosa!


Atmsfera PeligrosaSe requiere realizar algunas pruebas en las excavaciones que son mayores a 1.25m:Deficiencia de OxgenoAlta concentracin de gas combustible.Gases.Polvo.El monitoreo debe de ser continuo en situaciones de alto riesgo.


Sistema de Proteccin Inadecuado


Proteccin de los EmpleadosLos trabajadores deben de estar protegidos de derrumbes, usando un adecuado sistema de proteccin.

Los Sistemas de proteccin deben de resistir todas las cargas previstas en el momento de la excavacin.


Requerimientos de los sistemas de ProteccinUn Sistema de Proteccin bien Diseado Correcto Diseo de Pendientes y Sistema de Bancas. Corregir el diseo del sistema de soportes as como tambin otros sistemas de soporte para el cavado de zanjas. El trabajo debe tenerManipulacin apropiada de materiales y equipo. Atencin a las remociones de material y a las instalaciones dentro de la zanjaIgualdad En la proteccin de empleados en toda la zona de la excavacin.


Diseo de los Sistemas de ProteccinEl Empleador seleccionar y construir:cuestas y configuraciones de pendientes y de bancassistemas de soporte, sistemas de apuntalamiento, y otros sistemas protectores.Proteccin de Trincheras Puede ser permanente o temporal. Tambin conocido como caja de zanja o blindaje de zanja.Apuntalamiento Por ejemplo sistemas hidrulicos o mecnico, puede ser de madera o de metal, utilizado en las paredes de la excavacin. Pendiente - Un grado de inclinacin a las caras de una excavacin.


Proteja a sus empleadosexpuestos a derrumbespotencialesColoque pendientes o bancos en los lados de la excavacin.

Coloque soportes a los lados de la excavacin.

Colocar un resguardo entre los lados de la excavacin y la zona de trabajo.


Factores Implicados en elDiseo de un Sistema de ProteccinClasificacin de SueloProfundidad de Excavacin o de Corte.Contenido de agua en el sueloCambios debido al tiempo o climaOtras operaciones en las cercanas del lugar de trabajo


ApuntalamientoGeneral Proporciona una marco seguro de trabajo en las excavaciones. Soportes. Paredes de Excavacin.OSHA Proporciona tablas de los datos de Apuntalamiento. Debemos de saber el tipo de suelo. Debemos de saber el ancho y profundidad de la excavacin. Debemos de relacionarnos con los datos de la OSHA


Sistema de Proteccinde la TrincheraEl Sistema de Proteccin de la Zanja o Trinchera ser construido alrededor del rea de Trabajo.


Soporte hidrulico deZanjas o TrincherasAl utilizar sistemas hidrulicos el operador fcilmente puede caer en el orificio del sistema.

Una vez en el lugar, se debe de aumentar la presin para mantenerlo en el lugar.

Pernos de Zanja son instalados en caso de falla hidrulica.


Materiales y EquiposEl Equipo usado para los sistemas protectores no debe tener daos o defectos que afecten su operacin. El equipo daado debe ser revisado por una persona competente para poder verificar si el equipo puede ser utilizado.Al ser verificado y encontrar falla en el equipo, este deber ser quitado o ponerlo fuera de funcionamiento.


Proteccin Contra VehculosInstalar Barricadas rgidas.Seales y/o vigas.Seales de Pare.Retirar material de excavacin.Sealizacin de excavaciones en turno nocturno.


Material de RemocinNo colocar el material removido a menos 1m de distancia de el borde de la excavacin.Medir la parte ms cercana de los escombros a el borde de la excavacin. Mantener lneas de agua y alcantarillas lejos de la excavacin.Colocar los receptores de escombros lejos de la excavacin.


Medios de SalidaUna escalera o una rampa deben de estar presentes en una excavacin de mas de 1.25 m. (4 pies) de profundidad y a cada 7.5 m. (25 pies) para los empleados.Esta escalera no cumple con el requisito del estndarLas escaleras deben de extenderse por lo menos 1m. de la excavacin.


Ingreso y SalidaEstas 2 escaleras que se encuentran enlazadas juntas no son los medios adecuados de salida


Proteccin de cadas, de cada de material y equipos mviles Instalar berma de seguridad y/o barricadas.Utilizar seales y/o vigas.Retirar el material de las excavaciones lejos de la excavacin a 1m como mnimo.Utilizar barricadas, iluminadas para trabajos nocturnos.Utilizar vigas cuando las seales o barricadas no dan una suficiente proteccin.


Persona Competente Debe de tener un buen entrenamiento y estar bien informado sobre:Tipos de Terreno.Uso de sistemas protectores.Requisitos del estndar.Debe ser capaz de identificar peligros, y autorizado para eliminar inmediatamente cualquier riesgo.


Inspeccin de ExcavacionesUna persona competente debe de inspeccionar diariamente la excavacin, las reas alrededor y los sistemas de proteccin:Antes de empezar el trabajo verificar las salidas y las herramientas.


Inspeccin de ExcavacionesSi la persona competente encuentra, evidencia de un posible derrumbe, posibles fallas de los sistemas de proteccin, peligros atmosfricos u otras condiciones peligrosas debe:Retirar a los empleados de la zona de alto riesgo.Los empleados no pueden volver a reanudar su trabajo hasta que todos los riesgos sean controlados.


Anlisis de Riesgodel sitio de TrabajoAntes de empezar la Excavacin: Evaluar las condiciones y tipo de suelo. Construir sistemas de proteccin. Pruebas de deficiencia de oxigeno, gases combustibles y peligrosos Proporcionar acceso y salidas adecuadas. Determinar el EPP necesitado para esta tarea.Fisura


EXCAVACIONES PROFUNDASEn excavaciones de ms de 1, 25 m. de profundidad, los trabajadores que estn sin una adecuada proteccin debern tomar medidas de seguridad adicionales.


MEDIDAS PREVENTIVASSoporte, proteja, remueva estructuras adyacentes.

No excavar bajo ninguna estructura (excepto roca estable o con autorizacin del supervisor).

Estado mental alerta ante peligros potenciales que pueden surgir.2H


Mas de 1.25 mAPUNTALAR1.25 m.11Terreno Normal11/2Terreno Duro111/21.3 mt.MEDIDAS PREVENTIVASMETODO 1METODO 2METODO 3


MEDIDAS PREVENTIVASTipo A Arcilla, arcilla limosa y costra duraTipo B Limo, greda arenosa y arcilla medianaTipo C Grava, greda arenosa y arcilla blanda.CLASES DE SUELO


MEDIDAS PREVENTIVASMAXIMUM ALLOWABLE SLOPES

SOIL OR ROCK TYPEMAXIMUM ALLOWABLE SLOPES (H:V)(1) FOR EXCAVATIONS LESS THAN 20 FEET DEEP(3)STABLE ROCK TYPE A (2) TYPE B TYPE CVERTICAL (90) 3/4:1 (53) 1:1 (45) 1 :1 (34)


ResumenEl mayor riesgo en una excavacin son los derrumbes.Los empleados pueden ser protegidos a travs de pendientes, apuntalamiento, etc.Una persona competente es la encargada de inspeccionar la excavacin. Otros riesgos de la excavacin incluyen la acumulacin de agua, deficiencia de oxgeno, humos txicos, cadas y equipo mvil.


NO EXCAVES TU TUMBA !! TRABAJA CON SEGURIDAD


PROYECTO 320KEXCAVACIONESAMEC-VM

AGRADECE LA ATENCIN PRESTADA Y ESTAMOS SEGUROS QUE ESTA INFORMACION LE BENEFICIARA A USTED Y POR LO TANTO AL PROYECTO.

GRACIAS


1926 Subpart P Excavations

This presentation is designed to assist trainers conducting OSHA 10-hour Construction Industry outreach training for workers. Since workers are the target audience, this presentation emphasizes hazard identification, avoidance, and control not standards. No attempt has been made to treat the topic exhaustively. It is essential that trainers tailor their presentations to the needs and understanding of their audience.

This presentation is not a substitute for any of the provisions of the Occupational Safety and Health Act of 1970 or for any standards issued by the U.S. Department of Labor. Mention of trade names, commercial products, or organizations does not imply endorsement by the U.S. Department of Labor.

Reference 1926.650Shield (shield system) -- a structure able to withstand a cave-in and protect employees with the structure. Shields can be permanent structure or can be designed to be portable and moved along as work progresses. Also known as trench box or trench shield.

Shoring (shoring system) -- a structure such as a metal hydraulic, mechanical or timber shoring system that supports the sides of an excavation and which is designed to prevent cave-ins.

Sloping (sloping system) -- protects employees from cave-ins by excavating to form sides of an excavation that are inclined away from the excavation to prevent cave-ins. The angle of incline varies with differences in such factors as the soil type, environmental conditions of exposure, and application of surcharge loads.The discussion of this topic covers four main points. At the conclusion of the training, you should be able to:1. State the greatest risk that is present at an excavation.2. Briefly describe the three main methods for protecting employees from cave-ins.3. Name at least three factors that pose a hazard to employees working in excavations, and at least one way to eliminate or reduce each of the hazards. 4. Describe the role of a competent person at an excavation site. Instructor note: OSHA Standard Exemptions:House foundation/basement excavations (including those that become trenches by definition when formwork, foundations, or walls are constructed) are exempt from the OSHA standard. The specific information regarding the interpretation of this exemption may be found on the OSHA public web site. Reference 29 CFR 1926.652.

The exemption specifies height and width for the excavation, impact of water and environmental conditions, soil and equipment factors, and operation of heavy equipment in the vicinity.

Reference 1926.652(a) and 1926.652(c)(1)Designs for aluminum hydraulic shoring shall be in accordance with paragraph (c)(2), but if manufacturer's tabulated data cannot be utilized, designs shall be in accordance with appendix D.

Employees exposed to potential cave-ins must be protected by sloping or benching the sides of the excavation, by supporting the sides of the excavation, or by placing a shield between the side of the excavation and the work area.

1926 Subpart P Appendix D Aluminum Hydraulic Shoring for Trenches Contains information that can be used when aluminum hydraulic shoring is provided as a method of protection against cave-ins in trenches that are not more than 20 feet deep. In addition to the unprotected trench, a cave-in hazard is increased by machinery which gets too close.

Even normal vehicular traffic, such as that along an adjacent interstate or road through an industrial part may impact an excavation. The vibrations from continuous or heavy traffic may undermine the soil and cause a cave-in.1926.651(h)Employees shall not work in excavations in which there is accumulated water, or in excavations in which water is accumulating, unless adequate precautions have been taken to protect employees against the hazards posed by water accumulation. The precautions necessary to protect employees adequately vary with each situation, but could include special support or shield systems to protect from cave-ins, water removal to control the level of accumulating water, or use of a safety harness and lifeline.If water is controlled or prevented from accumulating by the use of water removal equipment, the water removal equipment and operations shall be monitored by a competent person to ensure proper operation.If excavation work interrupts the natural drainage of surface water (such as streams), diversion ditches, dikes, or other suitable means shall be used to prevent surface water from entering the excavation and to provide adequate drainage of the area adjacent to the excavation. Must also test where oxygen deficiency or a hazardous atmosphere could reasonably be expected to exist, before an employee enters the excavation.

If hazardous conditions exist, controls such as proper respiratory protection or ventilation must be provided. Also, controls used to reduce atmospheric contaminants to acceptable levels must be tested regularly.

Where adverse atmospheric conditions may exist or develop in an excavation, the employer also must provide and ensure that emergency rescue equipment, (e.g., breathing apparatus, a safety harness and line, basket stretcher, etc.) is readily available. This equipment must be attended when used.

Employees shall not be permitted to work in hazardous and/or toxic atmospheres. Such atmospheres include those with: -- less than 19.5% oxygen, -- a combustible gas concentration greater than 20% of the lower flammable limit, and, -- concentrations of hazardous substance that exceed those specified in the Threshold Limit Values for airborne contaminants established by the ACGIH.

Reference 1926.652(a) and (b) and (c)

Reference 1926.652(a)Protective system a method of protecting employees from cave-ins, from material that could fall or roll from an excavation face or into an excavation, or from the collapse of adjacent structures. Protective systems include support systems, sloping and benching systems, shield systems, and other systems that provide the necessary protection.

Several factors come into play when developing a total protective system. The design of of the system itself, how materials and equipment are handled in and around the excavation, and installation and removal of protective system components.Reference 1926.652, 1926.652(b), 1926.652(c)Benching -- excavating the sides of an excavation to form one or a series of horizontal levels or steps, usually with vertical or near-vertical surfaces between levels.Shoring or shielding is used when the location or depth of the cut makes sloping back to the maximum allowable slope impractical. There are two basic types of shoring, timber and aluminum hydraulic. Trench boxes (shielding) are different from shoring because instead of supporting the trench face, they are mostly serve to protect workers from cave-ins. The excavated area between the outside of the trench box and the face of the trench should be as small as possible. The space between the trench box and the excavation side may be backfilled (or other means may be used) to prevent lateral movement of the box. Shields may not be subjected to loads exceeding those which the system was designed to withstand. Trench boxes may be used in combination with sloping and benching.

Reference 1926.652(a)Each employee in an excavation shall be protected from cave-ins by an adequate protective system except when:Excavations are made entirely in stable rock; orExcavations are less than 5 feet in depth and examination of the ground by a competent person provides no indication of a potential cave-in.Protective systems shall have the capacity to resist without failure all loads that are intended or could reasonably be expected to be applied or transmitted to the system.

Reference 1926.652(b) Design of sloping and benching systems. 1926.652(c) The employer or his designee must select and construct designs of support systems, shield systems, and other protective systems

Trenches more than 5 feet require shoring or must have a stabilized slope

Trenches less than 5 feet - a competent person must inspect to determine that a protection system is not necessary in soils where there is no indication of a potential cave-in

In hazardous soil conditions trenches under 5 feet need protection

Reference 1926.652 (d)Materials and equipment used for protective systems shall be free from damage or defects that might impair their proper function.Manufactured materials and equipment used for protective systems shall be used and maintained in a manner that is consistent with the recommendations of the manufacturer, and in a manner that will prevent employee exposure to hazards.When material or equipment that is used for protective systems is damaged, a competent person shall examine the material or equipment and evaluate its suitability for continued use. If the competent person cannot assure the material or equipment is able to support the intended loads or is otherwise suitable for safe use, then such material or equipment shall be removed from service, and shall be evaluated and approved by a registered professional engineer before being returned to service.Reference 1926.651(f) Warning system for mobile equipmentWhen mobile equipment is operated adjacent to an excavation, or when such equipment is required to approach the edge of an excavation, and the operator does not have a clear and direct view of the edge of the excavation, a warning system shall be utilized such as barricades, hand or mechanical signals, or stop logs. If possible, the grade should be away from the excavation.

Reference 1926.651(j)(2) Protect employees from materials or equipment that could fall or roll into excavations.

You may also use retaining devices that are sufficient to prevent materials or equipment from falling or rolling into excavations

Reference 1926.651(c(1)Structural ramps- Structural ramps that are used solely by employees as a means of access or egress from excavations shall be designed by a competent person. Structural ramps used for access or egress of equipment shall be designed by a competent person qualified in structural design, and shall be constructed in accordance with the design.- Ramps and runways constructed of two or more structural members shall have the structural members connected together to prevent displacement.- Structural members used for ramps and runways shall be of uniform thickness. - Cleats or other appropriate means used to connect runway structural members shall be attached to the bottom of the runway or shall be attached in a manner to prevent tripping.- Structural ramps used in lieu of steps shall be provided with cleats or other surface treatments o the top surface to prevent slipping.Reference 1926.651(c) and 1926.1053 (ladder)

Falls and EquipmentTo protect employees from these hazards, OSHA requires the employer to take the following precautions: Keep materials or equipment that might fall or roll into an excavation at least 2 feet from the edge of excavations, or have retaining devices, or both. Provide warning systems such as mobile equipment, barricades, hand or mechanical signals, or stop logs, to alert operators of the edge of an excavation. If possible, keep the grade away from the excavation. Provide scaling to remove loose rock or soil or install protective barricades and other equivalent protection to protect employees against falling rock, soil, or materials. Prohibit employees from working on faces of sloped or benched excavations at levels above other employees unless employees at lower levels are adequately protected from the hazard of falling, rolling, or sliding material or equipment. Prohibit employees under loads that are handled by lifting or digging equipment. To avoid being struck by any spillage or falling materials, require employees to stand away from vehicles being loaded or unloaded. If cabs of vehicles provide adequate protection from falling loads during loading and unloading operations, the operators may remain in them.Reference 1926.650(b) "Competent person" One who is capable of identifying existing and predictable hazards in the surroundings, or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them.

Preamble Page 45909 Competent PersonThe term is used throughout existing subpart P, but was not defined within the subpart, and there were no references to the existing definition in subpart C, in the proposal, OSHA added the definition to subpart P to help those using the standard.

Reference 1926.651(k)Daily inspections of excavations, the adjacent areas, and protective systems shall be made by a competent person for evidence of a situation that could result in possible cave-ins, indications of failure of protective systems, hazardous atmospheres, or other hazardous conditions. An inspection shall be conducted by the competent person prior to the start of work and as needed throughout the shift. Inspections shall also be made after every rainstorm or other hazard increasing occurrence. These inspections are only required when employee exposure can be reasonably anticipated.Reference 1926.651(k)(2) Where the competent person finds evidence of a situation that could result in a possible cave-in, indications of failure of protective systems, hazardous atmospheres, or other hazardous conditions, exposed employees shall be removed from the hazardous area until the necessary precautions have been taken to ensure their safety.The following concerns must be addressed by a competent person: Evaluate soil conditions [1926 Subpart P Appendix A] and select appropriate protective systems [1926 Subpart P Appendix F]. Construct protective systems in accordance with the standard requirements [1926.652]. Preplan; contact utilities (gas, electric) to locate underground lines, plan for traffic control if necessary, determine proximity to structures that could affect choice of protective system. Test for low oxygen, hazardous fumes and toxic gases, especially when gasoline engine-driven equipment is running, or the dirt has been contaminated by leaking lines or storage tanks. Insure adequate ventilation or respiratory protection if necessary. Provide safe access into and out of the excavation. Provide appropriate protections if water accumulation is a problem. Inspect the site daily at the start of each shift, following a rainstorm, or after any other hazard-increasing event. Keep excavations open the minimum amount of time needed to complete operations. Surface crossing of trenches should not be made unless absolutely necessary. However, if necessary, they are only permitted under the following conditions:-- Vehicle crossings must be designed by and installed under the supervision of a registered professional engineer. -- Walkways or bridges must: -- have a minimum clear width of 20 inches, -- be fitted with standard rails, and -- extend a minimum of 24 inches past the surface edge of the trench.

Curso de Excavaciones

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