EN 1991 – Eurocode 1: Actions on structures Part 1-6 ... - Eurocodes

EUROCODESBackground and Applications<strong>EN</strong> <strong>1991</strong>-1-6: ContentsBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 3Section 4 Representation of actions4.1 General4.2 <strong>Actions</strong> on structural and non structural members duringhandling4.3 Geotechnical <strong>Actions</strong>4.4 <strong>Actions</strong> due to prestresssing4.5 Predeformations4.6 Temperature, shrinkage, hydration effects4.7 Wind <strong>Actions</strong>4.8 Snow Loads4.9 <strong>Actions</strong> caused by water4.10 <strong>Actions</strong> due to atmospheric icing4.11 Construction loads4.12 Accidental <strong>Actions</strong>4.13 Seismic <strong>Actions</strong>Paolo Formichi, University of Pisa Italy

EUROCODESBackground and Applications<strong>EN</strong> <strong>1991</strong>-1-6: AnnexesBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 4Annex A1(Normative)Supplementary rules for buildingsAnnexe A2 (Normative)Supplementary rules for bridgesAnnexe B(Informative)<strong>Actions</strong> on structures during alteration,reconstruction or demolitionPaolo Formichi, University of Pisa Italy

EUROCODESBackground and Applications<strong>EN</strong> <strong>1991</strong>-1-6: Design Situations and limit statesBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 7Any selected transient design situation be associated with anominal duration equal to, or greater than the anticipatedduration of the stage of execution under consideration.The design situations should take into account the likelihoodfor any corresponding return periods of variable actions (e.g.climatic actions).The return periods for the assessment of characteristic valuesof variable actions during execution may be defined in theNational Annex or for the individual project.Recommended return periods of climatic actions are given,depending on the nominal duration of the relevant designsituation.Paolo Formichi, University of Pisa Italy

EUROCODESBackground and Applications<strong>EN</strong> <strong>1991</strong>-1-6: Design Situations and limit statesBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 8Nominal duration of the execution phaseReturn period (years)A minimum wind velocity during execution may be defined in the National Annex orfor the individual project. The recommended basic value for durations of up to 3months is 20m/s in accordance with <strong>EN</strong> <strong>1991</strong>-1-4: Wind <strong>Actions</strong>.Relationships between characteristic values and return period for climatic actionsare given in the appropriate Parts of <strong>EN</strong> <strong>1991</strong>.Paolo Formichi, University of Pisa Italy

EUROCODESBackground and Applications<strong>EN</strong> <strong>1991</strong>-1-6: Design Situations and limit statesBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 9Example: Snow loads according to return period[Annex D of <strong>EN</strong> <strong>1991</strong>-1-3]If the available data show that the annual maximum snow load can beassumed to follow a Gumbel probability distribution, then therelationship between the characteristic value of the snow load on theground and the snow load on the ground for a mean recurrenceinterval of n years is given by:s kP nVsn=sk⎧⎪1−V⎨⎪⎪⎩6π[ ln( − ln(1 − P )) + 0,57722](1 + 2,5923V)is the characteristic snow load on the ground (with areturn period of 50 years)is the annual probability of exceedence (approx. = 1/n)is the coefficient of variation of annual max. snow loadsn⎫⎪⎬⎪⎪⎭Paolo Formichi, University of Pisa Italy

EUROCODESBackground and Applications<strong>EN</strong> <strong>1991</strong>-1-6: Design Situations and limit statesBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 10Snow loads according to return period[<strong>EN</strong> <strong>1991</strong>-1-3]1.001.000.900.900.800.800.700.70V = 0.2V = 0.6s n /s k0.600.600.500.500.400.400.300.300.200.200 5 10 15 20 25 30 35 40 45 500 5 10 15 20 25 30 35 40 45 50Return period (years)Paolo Formichi, University of Pisa Italy

EUROCODESBackground and Applications<strong>EN</strong> <strong>1991</strong>-1-6: Ultimate Limit StatesBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 11Ultimate limit states need to be verified for all selected transient,accidental and seismic design situations as appropriate duringexecution in accordance with <strong>EN</strong> 1990.The combinations of actions for accidental design situations can eitherinclude the accidental action explicitly or refer to a situation after anaccidental event.Generally, accidental design situations refer to exceptional conditionsapplicable to the structure or its exposure, such as: impact, local failure and subsequent progressive collapse, fall of structural or non-structural parts, and, in the case of buildings, abnormal concentrations of buildingequipment and/or building materials, water accumulation on steelroofs, fire, etc.Paolo Formichi, University of Pisa Italy

EUROCODESBackground and Applications<strong>EN</strong> <strong>1991</strong>-1-6: Ultimate Limit StatesBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 12The verifications of the structure should take into accountthe appropriate geometry and resistance of the partiallycompleted structure corresponding to the selected designsituations.Geometry of the partiallycompleted resisting structureResistance of the lower floor, whichhas not necessarily attained its fullstrength.Paolo Formichi, University of Pisa Italy

EUROCODESBackground and Applications<strong>EN</strong> <strong>1991</strong>-1-6: Ultimate Limit StatesBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 13geometryresistance1987 <strong>–</strong> Bridgeport Connecticut (US)Inadequate temporary connections +instability of steel members (*)(*) K. Carper “Beware of vulnerabilities during construction” -Construction and equipment, 3/20041973 - Bailey’s Crossroad <strong>–</strong> Fairfax (US)Construction of a 26-story building.Concrete was being placed at the 24 th floor andshoring was simultaneously being removed atthe 22 nd floor cast two weeks before.Insufficient shear resistance of concrete slabscaused progressive collapse (*)Paolo Formichi, University of Pisa Italy

EUROCODESBackground and Applications<strong>EN</strong> <strong>1991</strong>-1-6: Ultimate Limit StatesBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 14Ultimate limit states of STR/GEO - Fundamentalcombination for transient design situations.Expression (6.10) <strong>EN</strong> 1990∑∑γG, jGk, j"+ " γPP"+ " γQ,1Qk,1"+ "j≥ 1 i>1γQ,iψ0, iQk , iExpressions (6.10a) and (6.10b) <strong>EN</strong> 1990⎧⎪⎨⎪⎩∑j≥1∑j≥1γξG,jjγGG,jk , jG" + " γk , j0,85 ≤ ξ ≤ 1,00P" + " γP"+ "P∑i≥1P"+ " γγQ,iQ,1ψQ0, ik ,1Qk , i" + "∑i>1γQ,iψ0, iQk , iPaolo Formichi, University of Pisa Italy

EUROCODESBackground and Applications<strong>EN</strong> <strong>1991</strong>-1-6: Ultimate Limit StatesBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 15Accidental design situationExpression (6.11b) <strong>EN</strong> 1990∑∑Gk, j"+ " P"+ " Ad" + "(1,1or2,1)Qk,1"+ "j≥ 1 i>1ψψψ2, iQk , iSeismic design situationExpression (6.12b) <strong>EN</strong> 1990∑∑Gk, j"+ " P"+ " AEd" + "j≥ 1 i>1ψ2, iQk,iPaolo Formichi, University of Pisa Italy

EUROCODESBackground and Applications<strong>EN</strong> <strong>1991</strong>-1-6: Serviceability Limit StatesBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 16The SLS for the selected design situations duringexecution needs to be verified, as appropriate, inaccordance with <strong>EN</strong> 1990.The criteria associated with the SLS during executionshould take into account the requirements for thecompleted structure.Operations which can cause excessive cracking and/orearly deflection during execution and which may adverselyaffect the durability, fitness for use and/or aestheticappearance in the final stage has to be avoided.Paolo Formichi, University of Pisa Italy

EUROCODESBackground and Applications<strong>EN</strong> <strong>1991</strong>-1-6: Serviceability Limit StatesBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 17The combinations of actions should be established inaccordance with <strong>EN</strong> 1990. In general, the relevantcombinations of actions for transient design situationsduring execution are:the characteristic combinationthe quasi-permanent combinationPaolo Formichi, University of Pisa Italy

EUROCODESBackground and Applications<strong>EN</strong> <strong>1991</strong>-1-6: Serviceability Limit StatesBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 18∑SLS: : combinations of actions.Characteristic combination (irreversible SLS)∑Gk, j"+ " P"+ " Qk,1"+ "j≥ 1 i>1ψ0, iQk , iQuasi-permanent combination (reversible SLS)∑∑Gk, j"+ " P"+ "j≥1 i≥1ψ2, iQk , iPaolo Formichi, University of Pisa Italy

EUROCODESBackground and ApplicationsClassification & representation of actionsBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 19<strong>Actions</strong> during execution are classified in accordance with<strong>EN</strong> 1990, and may include:those actions that are not construction loads; andconstruction loadsBoth types of actions are classified (tables 2.1 and 2.2)depending on:Variation in time (permanent, variable, accidental)Origin (direct, indirect)Spatial variation (fixed, free)Nature (static, dynamic)Paolo Formichi, University of Pisa Italy

EUROCODESBackground and ApplicationsClassification & representation of actionsBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 20Paolo Formichi, University of Pisa Italy

EUROCODESBackground and ApplicationsConstruction LoadsBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 21Construction loads Q c may be represented in theappropriate design situations (see <strong>EN</strong> 1990), either, as onesingle variable action, or where appropriate different types ofconstruction loads may be grouped and applied as a singlevariable action. Single and/or a grouping of constructionloads should be considered to act simultaneously with nonconstruction loads as appropriate.Q caQ cbQ ccQ cdQ ceQ cf6 different sourcesPaolo Formichi, University of Pisa Italy

EUROCODESBackground and ApplicationsClassification of Construction LoadsBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 22Construction loads Q c are classified as variable actionsConstr.LoadQ caQ cbQ ccQ cdQ ceQ cfWhere Construction Loads are classified as fixed, they should be definedtolerances for possible deviation from the theoretical position.Where Construction Loads are classified as free, they should be defined limits ofthe area where they should be moved or positioned.Paolo Formichi, University of Pisa Italy

EUROCODESBackground and ApplicationsRepresentation of Construction LoadsBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 23Construction loads Q ca Personnel and hand toolsWorking personnel, staff and visitors, possibly with hand toolsor other small site equipment.Modelled as a uniformly distributed load q ca and applied as to obtainthe most unfavourable effects.The recommended value is : q ca,k = 1,0 kN/m 2Paolo Formichi, University of Pisa Italy

EUROCODESBackground and ApplicationsRepresentation of Construction LoadsBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 24Construction loads Q ca Personnel and hand toolsThe recommended value has been derived from investigations onconstruction sites(*), with regard to the following stages of construction:1. before pouring of concrete slab;2. after pouring of concrete slab, during the preparation of the next floor.Measurementgrid size [m 2 ]2,325,959,2520,9037,16Mean Load[kN/m 2 ]0,310,300,290,300,2810% fractileLoad [kN/m 2 ]As an example: the 5% fractile value for the 9,25 m 2 , is 1,23 kN/m 2 (Gumbeldistribution of the random variable is assumed).1,080,920,800,730,721% fractileLoad [kN/m 2 ](*) “Cast-in-place Concrete in Tall Building Design and Construction” <strong>–</strong> Council on Tall Buildings and UrbanHabitat Committee 21 D. Mc Graw-Hill Inc. <strong>–</strong> <strong>1991</strong> <strong>–</strong> Chapter 2: Construction loads.2,932,002,181,581,430,5% fractileLoad [kN/m 2 ]3,342,392,681,941,46Paolo Formichi, University of Pisa Italy

EUROCODESBackground and ApplicationsRepresentation of Construction LoadsBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 25Construction loads Q cb Storage of movable items e.g.:1. Building and construction materials, precast elements;2. Equipment.Modelled as a free action and represented by a UDL q cband a concentrated load F cbFor bridges, the following values are recommended minimumvalues:q cb,k = 0,2 kN/m 2F cb,k = 100 kNPaolo Formichi, University of Pisa Italy

EUROCODESBackground and ApplicationsRepresentation of Construction LoadsBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 26Construction loads Q cc Non-permanent equipment in positionfor use: Static (e.g. formwork panels, scaffolding, falsework, machinery,containers) During movement (e.g. travelling forms launching griders andnose, counterweights)Unless more accurate information is available, they may bemodelled by a uniformly distributed load with a recommendedminimum characteristic value of q cc,k = 0,5 kN/m 2Paolo Formichi, University of Pisa Italy

EUROCODESBackground and ApplicationsRepresentation of Construction LoadsBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 27Construction loads Q cd Movable heavy machinery andequipment usually wheeled or tracked e.g.:Cranes, lifts, vehicles, lift trucks, power installations, jacks, heavy liftingdevices.When not defined in the project specification, information for the determinationof actions may be found in:- <strong>EN</strong> <strong>1991</strong>-2 for actions due to vehicles- <strong>EN</strong> <strong>1991</strong>-3 for actions due to cranes.Paolo Formichi, University of Pisa Italy

EUROCODESBackground and ApplicationsRepresentation of Construction LoadsBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 28Construction loads Q ce Accumulation of waste materials e.g.:surplus construction materials excavated soil or demolition materials.These loads are taken into account by considering possible mass effects onhorizontal, inclined and vertical elements (such as walls).These loads may vary significantly, and over short time periods, depending ontypes of materials, climatic conditions, build-up and clearance rates.Paolo Formichi, University of Pisa Italy

EUROCODESBackground and ApplicationsRepresentation of Construction LoadsBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 29Construction loads Q cf Loads from part of structure in atemporary state before the final design actions take effect e.g. loadsfrom lifting operations.Taken into account and modelled according to the planned executionsequences, including the consequences of those sequences (e.g. loadsand reverse load effects due to particular processes of construction,such as assemblage).Paolo Formichi, University of Pisa Italy

EUROCODESBackground and ApplicationsRepresentation of Construction LoadsBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 30Construction loads during the casting of concrete (4.11.2)<strong>Actions</strong> to be taken intoaccount simultaneouslyduring the casting ofconcrete may include:- working personnel withsmall site equipment(Q ca );- formwork and loadbearingmembers (Q cc );- the weight of freshconcrete (which is oneexample of Q cf ), asappropriate.Paolo Formichi, University of Pisa Italy

EUROCODESBackground and ApplicationsRepresentation of Construction LoadsBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 31Q ca, Q ccand Q cfmay be given in the National Annex.Recommended values for fresh concrete (Q cf) may be taken from Table 4.2 and<strong>EN</strong> <strong>1991</strong>-1-1, Table A.1. Other values may have to be defined, for example, whenusing self-levelling concrete or pre-cast products.Paolo Formichi, University of Pisa Italy

EUROCODESBackground and Applications<strong>EN</strong> <strong>1991</strong>-1-6: Accidental <strong>Actions</strong>Brussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 32Accidental actions such as impact from construction vehicles, cranes,building equipment or materials in transit (e.g. skip of fresh concrete),and/or local failure of final or temporary supports, including dynamiceffects, that may result in collapse of load-bearing structural members,shall be taken into account, where relevant.Abnormal concentrations of building equipment and/or building materialson load-bearing structural members should also be taken into accountDynamic effects may be defined in the National Annex or for theindividual project. The recommended value of the dynamic amplificationfactor is 2. In specific cases a dynamic analysis is needed.Paolo Formichi, University of Pisa Italy

EUROCODESBackground and Applications<strong>EN</strong> <strong>1991</strong>-1-6: Seismic <strong>Actions</strong>Brussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 33Seismic actions should be determined according to<strong>EN</strong> 1998, taking into account the reference period of theconsidered transient situation.The design values of ground acceleration and the importancefactor γ I may be defined in the National Annex or for theindividual project.Paolo Formichi, University of Pisa Italy

EUROCODESBackground and Applications<strong>EN</strong> <strong>1991</strong>-1-6: Annex A1 (normative)Brussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 34Supplementary rules for buildingsRepresentative values of the variable action due to constructionloads may be set by the National Annex, within a recommendedrange of ψ 0 = 0,6 to 1,0.The recommended value of ψ 0 is 1,0.The minimum recommended value of ψ 2 is 0,2 and it is furtherrecommended that values below 0,2 are not selectedFor the verification of serviceability limit states, the combinations ofactions to be taken into account should be the characteristic andthe quasi-permanent combinations.Paolo Formichi, University of Pisa Italy

EUROCODESBackground and Applications<strong>EN</strong> <strong>1991</strong>-1-6: Annex A2 (normative)Brussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 35Supplementary rules for bridgesFor the incremental launching of bridges the design values for verticaldeflections may be found in the National Annex.The recommended values are:a) ± 10 mm longitudinally for one bearing, the other bearings beingassumed to be at the theoretical level;b) ± 2,5 mm in the transverse direction for one bearing, the otherbearings being assumed to be at the theoretical level.Paolo Formichi, University of Pisa Italy

EUROCODESBackground and Applications<strong>EN</strong> <strong>1991</strong>-1-6: Annex A2 (normative)Brussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 36Supplementary rules for bridges <strong>–</strong> Construction LoadsFor the incremental launching of bridges horizontal forces due to frictioneffects should be determined, and applied between the bridgestructure, the bearings and the supporting structures, with dynamicaction effects taken into account where appropriate.It is recommended that the design value of the total horizontal frictionforces should be not less than 10 % of the vertical loads, and shouldbe determined to give the least favourable effects.The horizontal friction forces at every pier should be determined with theappropriate friction coefficients, µ min and µ max (defined in the NationalAnnex).Unless more accurate values are available from tests for movements onvery low friction surfaces (e.g. PTFE) the recommended values are :µ min = 0µ max = 0,04Paolo Formichi, University of Pisa Italy

EUROCODESBackground and Applications<strong>EN</strong> <strong>1991</strong>-1-6: Annex B (informative)Brussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 37<strong>Actions</strong> on structures during alteration, reconstruction ordemolitionThe actual performance of structures affected by deterioration should betaken into account in the verification of the stages for reconstruction ordemolition. The investigation of structural conditions to enable theidentification of the load-bearing capacity of the structure and toprevent unpredictable behaviour during reconstruction or demolitionshould be undertaken.The reliability for the remaining structure or parts of the structure underreconstruction, partial or full demolition should be consistent with thatconsidered in the <strong>Eurocode</strong>s for completed structures or parts ofstructures.Paolo Formichi, University of Pisa Italy

EUROCODESBackground and ApplicationsBrussels, 18-20 February 2008 <strong>–</strong> Dissemination of information workshop 38Thank you for your attentionPaolo Formichi, University of Pisa Italy