Design manual for bridges vol. 6 section 2 td 41

Topographic Survey alias Ground Survey Collection of data to represent horizontal and vertical positions of an area, including features such as roads, bridges and bodies of water with contours, elevations and coordinates.

Is there a facility for obtaining a mobile emergency generator? Are there imaging equipment? Is there a gas system? What are the other essential equipment? Are there fire alarm and fire-fighting equipment? Compliance with R. LGU shall provide the appropriate equipment like chainsaws and other earthmoving and transport equipment. DPWH, c. The appropriate design flood to be adopted for different types of buildings is provided in Table A secondary evacuation route, such as a stairwell, should be provided that provides access to a level above the design flood level.

All electrical and related services should be above the design flood level, or flood proofed above the flood level.

Where inundation is expected to occur for more than a few hours, then provisions should be provided for appropriate evacuation. Market Stalls and Aisles A public market basically consists of stalls and aisles. A stall is the most important element of the market. In detailed design, great care must be exercised in analyzing the needs of vendors, particularly in the case of the wet stalls.

The stalls are designed with high flexibility to make them functional even if the original intention is changed. For planning purposes, the average sizes of the different market stalls may be assumed at 2—4 m2 per stall for vegetable, fruits, meat and dried fish, 5—9 m2 per stall for shops and sari-sari general store and 15—18 m2 for carinderia eatery and cereals.

For two storey market buildings, the dry markets stalls shall be situated at the upper level. The counter aisle should be at 1. The proposed dry section market stalls shall have a secure ceiling e. Maximum Space Requirements m2 Assistant Secretary Reception Room Other applicable space planning standards for other Philippine buildings i. Fixtures These are pieces of equipment or furniture that is fixed in position in a building or vehicle; articles attached to a building or land and considered legally part of it so that such items normally remain in place even when the building owner moves out; something securely fixed in place or attached as a permanent appendage, apparatus, or appliance e.

Equipment These are the necessary items for a particular purpose or activity; equipment solid state , apparatus, gear, material i. Use of organic soil treatment products. Minimization of over-paving through the requisite compliances with valid and subsisting laws, rules, regulations, guidelines, standards and procedural manuals pertaining to physical planning e.

Miscellaneous considerations i. Water conservation and management i. Solid waste management i. Indoor environment quality considerations e. Proper setbacks and compliance with mandated legal easements MLEs along waterways to maintain floodwater at a low level such as narrower waterways translate into higher flood levels.

If the use of metal roofs cannot be avoided, provide much steeper roof slopes because flatter slopes are easily penetrated by strong winds such as wind drag.

Use of roof that is sloped at all four 4 sides since typhoon winds come from all directions. Use of green roofs only when technically and financially feasible. Use of very short eaves i. Use of gutterless roofs in sites where trees shed a large volume of leaves i. Use of stilted or floating building technologies, if technically and financially feasible, if safe and if locally available. All emergency, exit and public doors servicing rooms or areas with users numbering twelve or more occupants must all swing outward and use nondetachable pins for added safety; if 2 exits are located in an enclosed space, these must be located far apart and at opposite sides of such space.

Avoidance of use of non-fire rated substances and materials for buildings, particularly those that produce toxic or harmful fumes during fire e. Use of medium-weight movable materials as furniture pieces i. Elevated floor finish line FFL at say 0.

Refer to Section 3. Positioning of convenience outlets above table surface height i. Use of jalousie windows, which are designed for use in the tropics, and which could serve as a fast means of escape but requires security provisions such grillwork or similar devices. Design of low-rise buildings for survivability i. Use of low-cost to optimum-cost devices or technologies than can readily convert seawater, brackish water, inland waterway water, wastewater, etc.

The NBCP has apparently been breached and violated at will over the last 36 years of its existence, resulting in the present pitiful state of the built environment. An architectural permit application must be accompanied by the pertinent architectural documents, together with computations that must be signed and sealed only by registered and licensed Architects RLAs , in full compliance with law Section The foregoing are only basic architectural plan and design features of the building.

Should the DPWH IRR on sustainable building design be promulgated, the RLA shall also be responsible for a number of sustainable building features, as well as features that address issues and concerns pertaining to climate change adaptation and disaster resilience.

The architectural permit application must clearly show that the building fully satisfies all the spatial requirements and all the applicable development controls DCs. The architectural permit application must also show the calculations for architectural life safety code compliances, particularly those mandated under R.

Also for inclusion is the satisfaction of the mandated compliances with B. Additionally, the pertinent information on architectural design features that address specific user needs and sensitivities must be included e.

RROW and the building grounds and enclosed building spaces. Dead Load Dead loads consist of the permanent weights and include the weight of columns, beams and girders, floor slab, roofing, walls, windows, plumbing, electrical fixtures, finishes and fixed equipment.

The minimum densities for design loads from materials are shown in Table The minimum values for dead loads in lowrise buildings are shown in Table Live Load Live load is determined by the function and occupancy of the building. Loads include the weights of temporarily placed items on the structure such as furnishings, human occupants and construction and maintenance activities.

All loads shall be the maximum loads expected by the intended use or occupancy and not be less than the loads required by this section. Live loads are provided in Tables , and Access floor systems Office use 2.

Sidewalks and driveways Computer use 4. Storage -- 7. Armories 3. Theaters, assembly areas3 and auditoriums 2 Stores Pedestrian bridges and walkways 7. Bowling alleys, poolrooms and similar recreational areas -- 3. Catwalk for maintenance access -- 1. Cornices and marquees -- 4 3. Dining rooms and restaurants -- 4. Exit facilities5 -- 4. Hospitals Libraries Manufacturing Office Printing plants Residential8 4 1 3 7 7 2 Storage 1.

Reviewing stands, grandstands, Bleachers, and folding and telescoping seating -- 4. Schools 2 4 Restrooms9 Stages areas 9. Assembly areas include such occupancies as dance halls, drill rooms, gymnasiums, playgrounds, plazas, terraces and similar occupancies that are generally accessible to the public.

Exit facilities shall include such uses as corridors serving an occupant load of 10 or more persons, exterior exit balconies, stairways, fire escapes Individual stair treads shall be designed to support a 1.

See Table for vehicle barriers Residential occupancies include private dwellings, apartments and hotel guest rooms. Restroom loads shall not be less than the load for the occupancy with which they are associated, but need not exceed 2. Construction, public access at site live load Walkway 7.

Grandstands, reviewing, stands bleachers, and folding and telescoping seating live load Seats and footboards 1. Stage accessories live load 4.

Ceiling framing live load 5. Flat or rise less than 4 units vertical in 12 units horizontal Arch and dome with rise less than one-eighth of span 1. Rise 4 units vertical to less than 12 units vertical in 12 units horizontal Arch and dome with rise one-eighths of span 0. Cranes dead and live loads Total load including impact increase 1. Balcony railings and guardrails Exit facilities serving an occupant load greater than 50 - 0.

Arch or dome with rise three-eighth of span or greater 0. Awnings except cloth covered. Greenhouses, lath houses and agricultural buildings. Vehicle barriers Handrails Storage racks Over 2. The maximum reduction, R, shall not exceed the value indicated in the table. Source: NSCP, 1 2 3 4 5 6 7 8 9 10 Vertical members of storage racks shall be protected from impact forces of operating equipment, or racks shall be designed so that failure of one vertical member will not cause collapse of more than the bay or bays supported by that member.

The 1. Notes for Table The tabulated loads are minimum loads. Where other vertical by this code or required by the design would cause greater stresses, they shall be used. Loads are in kPa unless otherwise indicated in the table. Does not apply to ceilings that have sufficient total access from below, such that access is not required within the space above the ceiling.

Does not apply to ceilings if the attic areas above the ceiling are not provided with access. This live load need not be considered as acting simultaneously with other live loads imposed upon the ceiling framing or its supporting structure. The impact factors included are for cranes with steel wheels riding on steel rails. They may be modified if substantiating technical data acceptable to the building official is submitted. Live loads on crane support girders and their connections shall be taken as the maximum crane wheel loads.

For pendant-operated traveling crane support girders and their connections, the impact factors shall be 1. This applies in the direction parallel to the runway rails longitudinal. The factor for forces perpendicular to the rail is 0. Forces shall be applied at top of rail and may be disturbed among rails of multiple rail cranes and shall be distributed with due regard for lateral stiffness of the structures supporting these rails.

Intermediate rails, panel fillers and their connections shall be capable of withstanding a load of 1. Reactions due to this loading need not be combined with those of Footnote 7. A horizontal load in kN applied at right angles to the vehicle barrier at a height of mm above the parking surface.

The force may be distributed over a mm-square area. The mounting of handrails shall be such that the completed handrail and supporting structure are capable of withstanding a load of at least N applied in any direction at any point on the rail.

These loads shall not be assumed to act cumulatively with Item 9. This is the dynamic effect on a body as induced by the contact of moving load or operating equipment. Impact is expressed as a percentage increase in the load when at rest. Soil load. Wind Load The most significant consideration in the computation of wind load is the location of the structure.

Areas facing the Pacific Ocean are analyzed against a maximum wind design velocity of kph and are designated as Zone 1, consistent with the strong tropical storms that originate from this area. The wind from Zone 1 wind weakens to kph in the area designated as Zone 2. Table 47 identifies specific provinces under each zone and a quick reference map is available on NSCP Figure NSCP also requires the use of the occupancy importance factor, a magnifier that increases or reduces the wind load.

Analysis of structures should include a separate consideration for the Main Wind Force Resisting System MWFRS which is the assembly of structural members that provide the overall reliability against wind forces, and the components and cladding elements which are individual parts of the structure that cover and complete the skeletal MWFRS.

The design wind load for buildings, including MWFRS and component and cladding elements, shall be determined using the following methods. Method 1: Simplified Procedure The steps in accordance with are: 1. Determine the exposure category or exposure coefficient Kz or Kh, as applicable for each wind direction in accordance with NSCP Section Pressure shall be applied simultaneously on windward and leeward walls and on roof surface as defined in NSCP Figures and All components and cladding.

Case 2: a: All main wind force resisting systems in buildings except those in low-rise buildings designed using NSCP Figure All main wind force resisting systems in other structures.

This factor shall only be applied when used in conjunction with load combinations specified in NSCP Section Exposure categories are defined in Section Method 3 — Wind Tunnel Procedure 4. Structures and portions thereof shall be designed and constructed to resist the effects of seismic ground motions as provided in NSCP Section Two methods of analysis are available, namely: Static Analysis and Dynamic Analysis.

The latter method may be used for any structure but is a must for structures described in Tables and and NSCP Section NSCP Section This approach is applicable to single family dwellings not more than three floors excluding the basement and also other structures not more than two stories excluding basement. Essential Facilities3 1. Hazardous Facilities 1. Special Occupancy Structures4 1.

Standard Occupancy Structure4 1. Miscellaneous Structures 1. For anchorage of machinery and equipment required for life-safety systems, the value of Ip shall be taken as 1. B All faults other than Types A and C. The source projection need not include portions of the source at deptsh of 10 km or greater. The largest value of the Near-source Factor considering all sources shall be used for design.

Bearing Wall Systems 4. Building Frame Systems B. Moment-Resisting Frame Systems D. Cantilevered Column Building Systems G. Regions are categorized as having the highest seismicity zone 4 to an area of least or lowest recorded seismic activity zone 1. Except for Palawan and some island provinces of Mindanao zone 2. The Philippines is under zone 4. This includes, soil type, proximity to earthquake generators and seismic source type which essentially predicts the magnitude that the fault can generate.

Stiffness Irregularity — Soft Story A soft story is one in which the lateral stiffness is less than 70 percent of that in the story above or less than 80 percent of the average stiffness of the three stories above.

Weight Mass Irregularity Mass irregularity shall be considered to exist where the effective mass of any story is more than percent of the effective mass of an adjacent story. A roof that is lighter than the floor below need not be considered. Vertical Geometric Irregularity Vertical geometric irregularity shall be considered to exist where the horizontal dimension of the lateral-force-resisting system in any story is more than percent of that in an adjacent story.

One-story penthouses need not be considered. Discontinuity In Capacity — Weak Story Irregularity A weak story is one in which the story strength is less than 80 percent of that in the story above. The story strength is the total strength of all seismic-resisting elements sharing the story for the direction under consideration. Interviews from the inhabitants of the area may also be done to cross-reference gathered historical data.

All projects require site investigations to be conducted by the duly authorized party. Site investigations must provide sufficient information for apt planning of the sub-surface investigation as determined by the engineer.

Recognition of the site hazards will prompt the engineers of the additional considerations critical to the investigation, design and analysis of the site. Anthropogenic Features Man-made structures and other appurtenances for water supply, power generation, agriculture, aquaculture, pumping wells, flood control, coastal improvement, land reclamations, sanitary landfills, slope stabilization, mining and quarrying, telecommunications, transportation, infrastructure and other edifices near the site constitute additional considerations.

A total of 2 boreholes for structures less than m2 in area and at least 3 boreholes for larger building area. A maximum of 1 borehole for every m2 of a structure. Topography and Geologic Features General features that must be noted are: Terrain analysis of the project site can be carried out using remotely-sensed imagery or topographical maps and then confirmed by conducting site reconnaissance surveys.

The project site is located on the map and the general surface environment and terrain can be interpreted. By identifying the terrain, specific issues can be taken into account such as sloping ground, soil and rock geologic formation, hydrologic formations, fault systems. The geologic information must provide insight to the regional geology of the site particularly soil and rock formation, groundwater table elevation, and other geotechnical characteristics.

Similarly, structures adjacent to project site must not experience disturbance, usually due to excessive vibrations and improperly designed excavations that may induce instability or aesthetic detriment such as misalignment of plumbing and door settling as determined by the Engineer. An overview of the rainfall patterns and climatic conditions is also ideal for holistic analysis as this provides an insight on the possible environmental conditions to be encountered in the construction and engineering process.

Drainage and surface water conditions may also provide useful information. Exposure to natural hazards must be comprehensively identified for sub-surface investigation and design references. Hazards cover natural and environmental factors that highly influence the stability and safety conditions of the project during and after construction.

Common risk factors include, but are not limited to, the following: Underground utility lines and other conduits 4. Sub-surface Investigations Sub-surface exploration shall observe the implementing rules and guidelines of governing agencies of national and local government, adapted international standards without compromising engineering principles and with high priority for safety the of stakeholders involved.

Geotechnical laboratories that will conduct tests must be ISOcertified and duly recognized to operate for local business. The laboratory tests will be conducted to determine the soil properties according to the rock sample recovered and the discretion of the geotechnical engineer on the soil parameters required for engineering design. In addition to the referenced guidelines, the DGCS shall also adopt additional guidelines from international standards, professional industry handbooks and globally used academic literature applicable for the implementation.

In this section, detailed discussion and instruction is provided on the 1 purpose and importance of sub-surface investigations; 2 proper execution of standard techniques and methodologies of soil explorations; and 3 output data analysis of field investigations for geotechnical reports. Execution of soil exploration methods shall integrate internationally-adopted standards and DPWH-observed guidelines. Various soil exploration methodologies will be discussed focusing on proper procedures, applicability to different soil and rock formations, and field considerations.

Analysis of information from field explorations shall include good practices in preparing boring logs and borehole logs to facilitate efficient geotechnical analysis. The Engineer must make sure that the measured groundwater table is not due to the drilling fluid used during boring.

Provisions for unprecedented irregularities during soil sub-surface explorations will be tackled in brevity. Geotechnical Laboratory Tests and Corresponding Standards Laboratory Test American Standard for Testing and Materials International Geotechnical Engineering Standards Sub-surface investigation must extend reasonably beyond the basement requirements of the project, if any.

Laboratory Tests Additional tests may be specified by the engineer as needed by the nature of the project. Allowable Soil Bearing Capacity To determine the allowable soil bearing capacity, the Geotechnical Engineer should use any widely accepted method in the industry to calculate for the ultimate soil bearing capacity.

The allowable soil bearing capacity qallow shall be a safe bearing capacity that Design Guidelines, Criteria and Standards: Volume 6 — Public Buildings and Other Related Structures exhibits settlement within the tolerable limits for the project. Tolerable settlement varies upon the nature of the project. Any anomalies in the stratification such as sand lenses and intercepted boulders must be noted and properly considered in the calculations and must be reflected in the report. Groundwater table effects on the soil bearing capacity must be considered.

The season when the field investigation was carried out must also be a factor; boring during dry season may decrease the groundwater table significantly while the wet season may increase it considerably as well. The method selected for the analysis must be compatible with the site soil type.

As recommended, the use of more than one method is advisable to determine a safe range of the allowable bearing capacity. From the results, a range of the allowable soil bearing capacity is provided for the structural engineer to adopt in the design calculations. Soil shear strength parameters cohesion and angle of internal friction must be determined in either drained or undrained conditions through laboratory testing or correlations. Deformation properties of the soil such as compression index, recompression index, coefficient of consolidation, elastic modulus must also be determined for settlement analysis.

Lateral Earth Pressure Lateral earth pressures are computed whenever the soil exerts horizontal pressures on structures particularly retaining walls, sheet piles, and excavation bracing. Refer Figure In computing for lateral earth pressures, widely-accepted theories and models may be used so as the applicability of the model is justifiable. Lateral earth pressures may be active or passive by character. When the horizontal pressure is less than the vertical pressure, the soil is under active case; otherwise, it is under passive case.

A structure may be subjected to both pressures at the same time depending on the geometry and other site conditions during different phases of construction. Eccentric loading Some of the authors of widely-used modified bearing capacity equations and comments regarding the use of their correction factors are provided in Table Deviations from the established procedures must all be noted during the procedure.

To monitor consolidation settlement, piezometers may be installed to observe changes in pore water pressure. Inclinometers and other soil movement gauges may as well be utilized by experienced users of such technology.

GeoHazards DGCS Volume 2A GeoHazard Assessment describes the nature of geohazards in the Philippines, the information required to assess their likelihood at a site, and a procedure for preparing a preliminary. As determined by the Engineer, special soil investigation must be carried out to determine the presence of problematic soil such as expansive soils, liquefiable soils, fractures and discontinuities in rock material.

Any uncommon condition in the subsurface material that will influence the project must be noted and properly investigated. Once the hazard is characterized by a Geotechnical Engineer, mitigating or remediating procedures may be applied. Any widely-accepted soil or rock improvement method may be conducted as long as it is identified by the Engineer as appropriate to the site condition. Shallow foundations are designed accordingly to exert pressures less than the allowable soil bearing capacity.

In the design of shallow foundations, project requirements for basement levels are major factors. The basement level will determine the depth of the foundation and may prompt the engineer to decide between using shallow or deep foundation. The footing design will observe the provisions of NSCP for structural concrete. Effects may be dealt with using any modification in the footing design that is permissible given the particular restraints of the project.

Deep Foundations Pile Design Deep foundation is used when the soil support mechanism relies on the skin friction and end bearing of the foundation against the soil. Deep foundations are used when soil bearing capacity is not enough to support the weight of the structure, if the upper soil strata are weak, and if the project is off-shore or subjected to high groundwater table.

Accessibility and adjacent structures are some other considerations for the use of deep foundations. Two general schemes of pile installation may be chosen by the engineer: driven piles and bored piles. Driven piles requires installation of precast piles on-site using a pneumatic or drop hammer heavy equipment. The installation procedure causes significant noise and vibration to induce public disturbance and structural damage to adjacent structures.

This method, however, effectively mobilizes the skin friction resistance of the soil. Driven piles also facilitate construction. Bored piles require on-site assembly of reinforcing bars and preparation of drilled hole. The rebar skeleton is lowered into the hole and filled with concrete mix delivered on site. Before the concrete is poured onto the hole, debris and other dirt must be removed from the bottom of the hole to ensure the load transfer mechanism of the pile.

Significant noise or public disturbance and structural damage must not be caused within proximal area of the project. This method effectively mobilizes the end-bearing more than the skin friction resistance of the soil. Bored piles relatively take a little more time than driven piles to install.

Any widely-accepted method can be used to estimate pile capacity. Pile capacity mainly relies on two components which are point- or end-bearing resistance and skin friction.

End-bearing capacity depends on the stratum on which the pile end rests. Skin friction is the frictional force exerted by the soil surrounding the pile through its embedment length. Grouped piles must be placed as near each other as required by space allotment but more importantly, as far from each other for skin friction to develop and mobilize.

The limiting distance between piles must be specified by the attending engineer. Micropiles Micropiles are bored mini piles with diameter not exceeding mm. Because of the small size of mini piles, only small dimension equipment is needed for construction and can be used to drill through any type of soils, boulders and hard materials.

They are constructed using high strength small diameter casing or thread bar. Typically the casing is advanced to the design depth using a drilling technique. Reinforcing steel in the form of an all-thread bar is typically inserted Design Guidelines, Criteria and Standards: Volume 6 — Public Buildings and Other Related Structures into the micropile casing.

High strength cement grout is then pumped into the casing. The casing may extend to the full depth above the bond zone with the reinforcing bars extending to the full depth. The finished micropile resists compression, uplift or tension loads and lateral loads. The design of micropiles for buildings and bridges involves the same approach. Strain compatibility under compression load is considered for the steel components and grout by limiting allowable stresses to the minimum allowable for any individual component i.

Therefore, the maximum yield stress of steel to be used in the above equation is the minimum of yield stress of casing, yield stress of steel reinforcing rod and maximum stress based on grout failure. The reinforcing bar should be designed to carry the entire tension design load.

Since a micropile can be subjected to lateral loads or overturning moments, they are subject to bending stresses also, thus requiring combined stress evaluation. In this equation, it is conservatively assumed that the maximum axial compression load, Pc , is carried by the steel casing only and the yield stress of the steel casing is used. The outside diameter of the steel casing is reduced to account for losses due to corrosion in the computation of the allowable compression capacity of a cased length.

Also, if the micropile is used in very weak ground, the allowable compression load may be reduced to consider the effect of buckling over the length of the micropile.

Depths of unsupported or unbraced excavation must not exceed 3 m unless the conditions are deemed stable and safe by the Geotechnical Engineer. The Geotechnical Engineer must account for several factors like in-situ soil parameters, access, groundwater table and overall intent in excavating. If the groundwater is relatively shallow, dewatering may be employed, however, caution is advised so as not to cause structural damage or significant settlement to adjacent structures.

Observation wells may also be installed near the excavation sites to monitor dewatering progress and effects. To design the support system for excavations, rain conditions must be considered in the design observing the principles on lateral earth pressure in Section 4.

Methods such as shotcrete application, soil nailing and other soil reinforcement methods for excavations can be used as long as it is supervised by experienced engineers in using the technology.

The optimum moisture content will be determined in the laboratory using applicable standard methods. Every layer in the compacted fill in the field shall be tested according to the specifications.

In the selection of the fill material, special consideration must be given to the use of the fill material particularly with the hydraulic properties of the structure. The limit of MPa is to prevent grout crushing at an assumed strain of 0. Structural Detailing NSCP Section In general, this section shall be used as reference in detailing requirements for constructability and ensure that placement of reinforcement is consistent with the design intent. This will also define the number of bars that can be accommodated per layer of bar in flexural members which in turn shall be used in the computation of effective depth.

It specifies the minimum concrete cover for cast-in-place concrete and precast concrete both for non prestressed and prestressed members. These are usually provided in structural slabs where the flexural reinforcement extend in one direction only. This is applicable for non-prestressed reinforced concrete members which are allowed to be designed using service loads without load factors and permissible load stresses.

Flexure and Axial Load NSCP Section Flexure and axially loaded members shall be analyzed using accepted classical methods with due consideration for all possible loads and load combinations. This section of the code provides basic assumptions and minimum requirements that needs to be satisfied. Help us improve the content on our website or tell us what is working well.

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You are here: Home Business and industry Technical publications. Design manual for roads and bridges DMRB 6. Revision 1 - March , updates references. Revision 0 - November Highways England and the Department for Transport have announced the organisation will become National Highways.

It operates, maintains and improves England's motorways and major A roads. It is an executive non-departmental public body, sponsored by the Department for Transport and was previously known as Highways Agency.