Abstract In this report studies have been made about variations in impact sound insulation from 20 Hz in an industrial, prefabricated, light weight apartment building. The building was constructed by Lindbäcks Bygg AB. Variations was determined from measurement method from SS16283-2:2015 and due to the workmanship of the structure. The different measurement methods from SS16283-2:2015 was also analyzed, the difference in sound pressure level and measurement uncertainty was checked. The objective with this report is to verify if the current standard is adaptable for measurement from 20 Hz in a prefabricated apartment building. Also verifying the standard and if possible make the procedure of measurement more effective. Measurement of sound insulation were executed in 12 apartments. The apartment was of the same prefabricated module. From the measurements the impact sound insulation was calculated and was presented in both measurement methods and from 20 Hz. Variations of impact sound insulation was quantitated from 20 Hz with one normalized value for a simulated reverberation time under 50 Hz and one without correction of reverberation under 50 Hz. The calculated value of variation due to the measurement method was not of some significant difference, this indicate the current standard is adaptable for measurements from 20 Hz. The variation due to workmanship was quantitated, but no statistical analyze could be made cause lack amount of measurements. A significant difference in sound pressure level was identified between measurement methods, this was assumed to be caused by the room modes. / I detta examensarbete utvärderas variationer i stegljudsnivå från 20 Hz i ett industriellt prefabricerat flerbostadshus uppfört med trästomme. Variationerna sett till mätmetod och utförandet av konstruktionen kontrollerades. Det genomfördes även en kontroll mellan mätmetoder angivna av SS16283-2:2015 om det uppstod någon skillnad sett till uppmätt ljudtrycksnivå och mätosäkerhet. Målet med projektarbetet var att kontrollera om går att anpassa dagens standard för mätningar från 20 Hz. Samt kontrollera de olika mätmetoder angivna av SS16283-2:2015 kvalitet, detta för att effektivisera och ge möjlighet till en högre kvalitet av genomförda mätuppdrag för Tyréns AB. Ljudmätningar genomfördes i ett industriellt prefabricerat flerbostadshus uppfört av Lindbäcks Bygg. Byggnadsprojektet kallas för Sofiehem 61 och är ett studentboende. Byggnaden består av fem våningar varav en vindsvåning som enbart är till för installationer. Varje plan består av åtta lägenheter bortsett bottenplan där enbart sju lägenheter finns. Det genomfördes totalt mätningar i 12 identiska lägenheter uppförda med samma byggnadsmodul. Från de genomförda mätningarna kunde stegljudsnivån beräknas och redovisas utifrån de aktuella mätmetoderna och från 20 Hz. Det uppstod ingen markant variation sett till mätmetoden vid mätningar ner till 20 Hz, detta indikerar på att dagens mätstandard går att tillämpa för mätningar ner till 20 Hz. Variationen sett till stegljudsnivå för konstruktionens utförande kvantifierades, dock genomfördes mätningar på för få mätobjekt för att erhålla statistiskt korrekta resultat. Det uppstod däremot en skillnad sett till stegljudsnivåer vid val av mätmetod angiven av S16283- 2 2015. Detta bedömdes bero på rummets egenfrekvens.

Impact sound can be caused, for example, by children jumping and playing or by other types of mechanical contact with the structure. Insufficient impact sound insulation in lightweight timber structures is a recurring issue and is of great importance for the overall quality assessment of residential buildings. Impact sound is a complex topic that, together with a lack of understanding in the industry, often results in contractors building first and testing later. This methodology often leads to costly measures at the end of the construction process.  In recent years, much research has been conducted to investigate the impact sound problem in lightweight timber structures, but few studies have focused on the relationship between impact sound level and vibration, which is investigated in this study. Through field measurements of impact sound and vibration in three different buildings, information was expected to be obtained on how the design of floors and joints can affect the impact sound insulation. The purpose of obtaining this information was to simplify the evaluation of buildings' final construction. A conclusion that can be drawn from the study is that insufficient impact sound insulation is expected to be due to lower damping in the joints. With greater damping in the joints, the evaluation of the final design can be simplified, as the transmission paths are limited to mainly through the floor. / Stegljud kan uppstå genom barns hopp och lek eller vid annan typ avmekanisk kontakt med stommen. Bristande stegljudsisolering i lättaträkonstruktioner är ett återkommande problem och är av stor betydelse förden totala kvalitetsbedömningen av bostäder. Stegljudsproblematik är ettkomplext ämne som tillsammans med en bristande förståelse i branschen,ofta resulterar i att entreprenörer bygger först och testar senare. Dennametodik leder inte sällan till kostsamma åtgärder i byggprocessensslutskede.Under senare år har mycket forskning bedrivits i syfte att utredastegljudsproblematiken i lätta träkonstruktioner, men få studier har fokuseratpå relationen mellan stegljudsnivå och vibrationer, som undersöks i dennastudie. Genom fältmätningar av stegljud och vibrationer i tre olikabyggnader, förväntades information erhållas kring hur utformning avbjälklag och knutpunkter kan påverka stegljudsisoleringen. Syftet med attinhämta denna information var att förenkla värderingen av byggnadersslutgiltiga konstruktion.En slutsats som kan dras från studien är att bristande stegljudsisoleringförväntas bero på lägre dämpning i knutpunkterna. Med större dämpning iknutpunkterna kan värderingen av slutlig konstruktion förenklas, detta dåtransmissionsvägarna begränsas till i huvudsak genom bjälklaget.

This report's aim is that by field measurements determine the function of Aprobo soundproofing material dB2 for reducing impact sounds, the measurements is done in “the school for fine art” in Umeå also known as “konstnärligt campus building nine”. The construction technique is used in areas sensitive to impact sound between different floors in the building. The measurement’s is also to do a function control of the buildings sound quality compared to Swedish and European standard when it comes to air sound, impact sound and reverberation time . The report have concluded that the function of Aprobo dB2 as an impact isolation is correct but that it have no positive result on the air sound isolation in nether horizontally or vertically when controlled in weighted values. The report’s conclusions can be used in future projections of buildings that suffer from impact sensitivity in vertical direction, it can also be used to project for impact sound isolation in horizontal direction but that it is important to choose the proper construction above the isolation for that to work. / Syftet med detta arbete är att genom fältmätning fastställa funktionen av Aprobos ljuddämpningsmatta dB2 och hur väl den reducerar stegljud. Mätningarna är genomförda på konsthögskolans byggnad i Umeå även kallad byggnad nio på konstnärligt campus. Den aktuella tekniken används i konstruktioner känsliga för ljudtransport mellan våningsplan. Undersökningens syfte är även att göra en funktionskontroll av byggnadens ljudstandard jämnfört med Svensk och Europeisk standard för såväl luftljud, stegljud och efterklangstid.  Rapporten har kommit fram till att Aprobos konstruktionslösning med dB2 har en positiv inverkan på stegljudsisolering men att den ej har någon positiv inverkan på luftljudsisolering vare sig i vertikal eller horisontalled när de kontroleras i vägda värden. Rapportens slutsats går att användas i framtida projekt av byggnader som är känsliga för stegljud i vertikalled, den går även använda vid projektering av stegljud i horisontalled men då är det viktigt att rätt konstruktionslösning väljs för övergolvet.

Denna avhandling behandlar stegljudet i två trähus på campus i Växjö. Staden lyfts ofta fram som en bra förebild inom miljö- och klimatfrågor. Det kommunala fastighetsbolag som äger, förvaltar och bygger universitetets byggnader är intresserade av dessa frågor när nya hus ska byggas. De två senast byggda husen är byggda med trästomme, som anses vara ett bra miljöval. Framtida hus förväntas även de byggas med trästomme. Dessvärre lyfts ofta problem angående akustiken upp i hus med trästomme. Ett av de befintliga husen på universitetsområdet sägs ha problem med stegljud och fastighetsägaren vill att detta potentiella problem bör förbättras för framtida byggnader. Syftet med denna studie är att konstatera hur akustiken i en framtida universitetsbyggnad med trästomme bör uppfattas och vilka stegljudskrav som bör ställas på byggnaden för att upplevelsen ska vara tillfredställande. För att få den kunskap utförs en enkätundersökning och stegljudsmätningar av de befintliga husen för att kartlägga vad som uppfattas som en tillfredsställande ljudmiljö. / This thesis deals with the impact sound of two wooden buildings on the campus site in Växjö. The city is highlighted frequently as a good model on environmental and climate issues. The municipal real estate company that owns, manages and builds the university's buildings, is interested in these issues when building new houses. The two most recently built houses are constructed with wooden frames, which is considered a good environmental choice. Future house is also expected to be built with wooden frames. Unfortunately problems due to acustics are often raised. One of the existing houses at the university are said to have problems with its impact sound and the property owner want this potential problem to be improved for future buildings. The purpose of this study is to gain knowledge from two existing wooden houses in the area. To do this a survey investigating how the acoustics of the buildings are perceived is compared with measurement of impact sound measurements.

An increased share of construction with timber is one possible way of achieving more sustainable and energy-efficient life cycles of buildings. The main reason is that wood is a renewable material and buildings require a large amount of resources. Timber buildings taller than two storeys were prohibited in Europe until the 1990s due to fire regulations. In 1994, this prohibition was removed in Sweden.     Some of the early multi-storey timber buildings were associated with more complaints due to impact sound than concrete buildings with the same measured impact sound class rating. Research in later years has shown that the frequency range used for rating has not been sufficiently low in order to include all the sound characteristics that are important for subjective perception of impact sound in light weight timber buildings. The AkuLite project showed that the frequency range has to be extended down to 20 Hz in order to give a good quality of the rating. This low frequency range of interest requires a need for knowledge of the sound field distribution, how to best measure the sound, how to predict the sound transmission levels and how to correlate numerical predictions with measurements.     Here, the goal is to improve the knowledge and methodology concerning measurements and predictions of low frequency impact sound in light weight timber buildings. Impact sound fields are determined by grid measurements in rooms within timber buildings with different designs of their joist floors. The measurements are used to increase the understanding of impact sound and to benchmark different field measurement methods. By estimating transfer functions, from impact forces to vibrations and then sound pressures in receiving rooms, from vibrational test data, improved possibilities to correlate the experimental results to numerical simulations are achieved. A number of excitation devices are compared experimentally to evaluate different characteristics of the test data achieved. Further, comparisons between a timber based hybrid joist floor and a modern concrete floor are made using FE-models to evaluate how stiffness and surface mass parameters affect the impact sound transfer and the radiation.     The measurements of sound fields show that light weight timber floors in small rooms tend to have their highest sound levels in the low frequency region, where the modes are well separated, and that the highest levels even can occur below the frequency of the first room mode of the air. In rooms with excitation from the floor above, the highest levels tend to occur at the floor levels and in the floor corners, if the excitation is made in the middle of the room above. Due to nonlinearities, the excitation levels may affect the transfer function in low frequencies which was shown in an experimental study. Surface mass and bending stiffness of floor systems are shown, by simulations, to be important for the amount of sound radiated.     By applying a transfer function methodology, measuring the excitation forces as well as the responses, improvements of correlation analyses between measurements and simulations can be achieved / <p>Opponent:Kari, Leif, Professor</p><p>Handledare: Linderholt, Andreas, Lektor</p><p>ProjektProWoodSilent Timber BuildUrban TranquilityBioInnovation FBBB</p><p>Forskningsfinansiär: KK-stiftelsen</p><p>Delarbeten:</p><p>1. Low frequency measurements of impact sound performance in light weight timber frame office buildings</p><p>2. Low frequency sound pressure fields in small rooms in wooden buildings with dense and sparse joist floor spacings</p><p>3. Low Frequency Force to Sound Pressure Transfer Function Measurements Using a Modified Tapping Machine on a Light Weight Wooden Joinst Floor4. Impact evaluation of a thin hybrid wood based joist floor</p>

An increased share of construction with timber is one possible way of achieving more sustainable and energy-efficient life cycles of buildings. The main reason is that wood is a renewable material and buildings require a large amount of resources. Timber buildings taller than two storeys were prohibited in Europe until the 1990s due to fire regulations. In 1994, this prohibition was removed in Sweden.     Some of the early multi-storey timber buildings were associated with more complaints due to impact sound than concrete buildings with the same measured impact sound class rating. Research in later years has shown that the frequency range used for rating has not been sufficiently low in order to include all the sound characteristics that are important for subjective perception of impact sound in light weight timber buildings. The AkuLite project showed that the frequency range has to be extended down to 20 Hz in order to give a good quality of the rating. This low frequency range of interest requires a need for knowledge of the sound field distribution, how to best measure the sound, how to predict the sound transmission levels and how to correlate numerical predictions with measurements.     Here, the goal is to improve the knowledge and methodology concerning measurements and predictions of low frequency impact sound in light weight timber buildings. Impact sound fields are determined by grid measurements in rooms within timber buildings with different designs of their joist floors. The measurements are used to increase the understanding of impact sound and to benchmark different field measurement methods. By estimating transfer functions, from impact forces to vibrations and then sound pressures in receiving rooms, from vibrational test data, improved possibilities to correlate the experimental results to numerical simulations are achieved. A number of excitation devices are compared experimentally to evaluate different characteristics of the test data achieved. Further, comparisons between a timber based hybrid joist floor and a modern concrete floor are made using FE-models to evaluate how stiffness and surface mass parameters affect the impact sound transfer and the radiation.     The measurements of sound fields show that light weight timber floors in small rooms tend to have their highest sound levels in the low frequency region, where the modes are well separated, and that the highest levels even can occur below the frequency of the first room mode of the air. In rooms with excitation from the floor above, the highest levels tend to occur at the floor levels and in the floor corners, if the excitation is made in the middle of the room above. Due to nonlinearities, the excitation levels may affect the transfer function in low frequencies which was shown in an experimental study. Surface mass and bending stiffness of floor systems are shown, by simulations, to be important for the amount of sound radiated.     By applying a transfer function methodology, measuring the excitation forces as well as the responses, improvements of correlation analyses between measurements and simulations can be achieved / ProWood / Silent Timber Build / Urban Tranquility / BioInnovation FBBB

This doctoral thesis concerns flanking transmission in light weight, wooden multi-storey buildings within the low frequency, primarily 20-120 Hz. The overall aim is to investigate how the finite element method can contribute in the design phase to evaluate different junctions regarding flanking transmission. Two field measurements of accelerations in light weight wooden buildings have been evaluated. In these, two sources; a stepping machine, and an electrodynamic shaker, were used. The shaker was shown to give more detailed information. However, since a light weight structure in field exhibit energy losses to surrounding building parts, reliable damping estimates were difficult to obtain. In addition, two laboratory measurements were made. These were evaluated using experimental modal analysis, giving the eigenmodes and the damping of the structures. The damping for these particular structures varies significantly with frequency, especially when an elastomer is used in the floor-wall junction. The overall damping is also higher when elastomers are used in the floor-wall junction in comparison to a screwed junction. By analysing the eigenmodes, using the modal assurance criterion, of the same structure with two types of junctions it was concluded that the modes become significantly different. Thereby the overall behavior differs. Several finite element models representing both the field and laboratory test setups have been made. The junctions between the building blocks in the models have been modeled using tie or springs and dashpots. Visual observation and the modal assurance criterion show that there is more rotational stiffness in the test structures than in the models. The findings in this doctoral thesis add understanding to how modern joints in wooden constructions can be represented by FE modelling. They will contribute in developing FE models that can be used to see the acoustic effects prior to building an entire house. However, further research is still needed. / Denna doktorsavhandling behandlar flanktransmission i flervåningshus med trästomme, inom det lågfrekventa området, främst 20-120 Hz. Det övergripande målet är att undersöka hur finita elementmetoden kan bidra i konstruktionsfasen för att utvärdera olika knutpunkters inverkan på flanktransmissionen. Två fältmätningar av accelerationer i trähus har utvärderats. I dessa har två olika lastkällor använts, i den första en stegljudsapparat och i den andra en elektrodynamisk vibrator (shaker). Det visades att shakern kan ge mer detaljerad information, men eftersom vibrationerna även sprider sig till omgivande byggnadsdelar vid fältmätningarna var det svårt att estimera tillförlitliga dämpningsdata även då shaker användes. Fältmätningarna följdes av två mätningar i laborationsmiljö. Dessa två experiment utvärderades med experimentell modalanalys, vilket ger egenmoder och dämpning hos strukturerna. Dämpningen för dessa trähuskonstruktioner varierar kraftigt med frekvens. Extra stora variationer registreras då en elastomer användes i knutpunkten mellan golv och vägg. Den totala dämpningen är generellt högre när elastomerer används i knutpunkten mellan golv och vägg i jämförelse med då knutpunkten är skruvad. Genom att analysera egenmoder och deras korrelationer (MAC), för samma trästruktur men med olika typer av knutpunkter, drogs slutsatsen att knutpunkten drastiskt förändrar strukturens dynamiska beteende. Flera finita elementmodeller av både fält- och laboratorieuppställningar har gjorts. I dessa har knutpunkterna mellan byggnadsdelar modellerats helt styvt eller med hjälp av fjädrar och dämpare. Visuella observationer av egenmoder och korrelationen dem emellan visar att det finns mer rotationsstyvhet i försöken än i finita elementmodellerna. Resultaten i denna doktorsavhandling har gett förståelse för hur knutpunkter i träkonstruktioner beter sig och kan simuleras med finit elementmodellering. Vidare kan resultaten bidra till utvecklingen av FE-modeller som kan användas för att kunna se de akustiska effekterna redan under konstruktionsstadiet. Dock behövs ytterligare forskning inom området.